Two women wearing masks sit and talk on the boardwalk near a warning sign to stop the coronavirus disease (COVID-19) during Memorial Day weekend in Bethany Beach, Delaware, U.S., May 24, 2020. REUTERS/Kevin Lamarque

A visitor to the boardwalk passes a warning sign to stop the coronavirus disease (COVID-19) during Memorial Day weekend in Bethany Beach, Delaware, U.S., May 24, 2020. REUTERS/Kevin Lamarque

A sign warns of the coronavirus disease (COVID-19) outbreak at the Vietnam Veterans Memorial in Washington, U.S., May 24, 2020. REUTERS/Joshua Roberts

A sign warns of coronavirus disease (COVID-19) during Memorial Day weekend at the Lincoln Memorial in Washington, U.S., May 24, 2020. REUTERS/Joshua Roberts

A sign warns of coronavirus disease (COVID-19) during Memorial Day weekend at the Lincoln Memorial in Washington, U.S., May 24, 2020. REUTERS/Joshua Roberts

A police officer gives warning to Muslims praying outside the closed National Mosque, during Eid al-Fitr, the Muslim festival marking the end the holy fasting month of Ramadan, amid the coronavirus disease (COVID-19) outbreak in Kuala Lumpur, Malaysia May 24, 2020. REUTERS/Lim Huey Teng

Muslims disperse after they were warned by police officers outside the closed National Mosque while celebrating Eid al-Fitr, the Muslim festival marking the end the holy fasting month of Ramadan, amid the coronavirus disease (COVID-19) outbreak in Kuala Lumpur, Malaysia May 24, 2020. REUTERS/Lim Huey Teng

May 21, 2020; Tuscaloosa, AL, USA; A sign at the entrance of Bryant-Denny Stadium warning people to keep the six feet safety difference. Mandatory Credit: Marvin Gentry-USA TODAY Sports

A warning sign is seen at the entrance to the reservoir, amid the coronavirus disease (COVID-19) outbreak, in Farmoor Reservoir, Farmoor, Britain, May 15, 2020. Picture taken May 15, 2020. REUTERS/Paul Childs

A sign warns visitors against touching it after coronavirus disease (COVID-19) restrictions were lifted at the Topeka Zoo in Topeka, Kansas, U.S., May 14, 2020. REUTERS/Nate Chute

Warning signs are posted at the entrance of a pool during the outbreak of the coronavirus disease (COVID-19), in Pasadena, California, U.S., May 10, 2020. Picture taken May 10, 2020. REUTERS/Mario Anzuoni

Fishermen dangle their lines to catch fish at Beirut's seaside Corniche, as Lebanese authorities warned of a new wave of the coronavirus disease (COVID-19) as the numbers jumped to the highest point in more than a month, after the government eased some restrictions on public life, in Beirut, Lebanon May 10, 2020. Picture taken May 10, 2020. REUTERS/Mohamed Azakir

People walk and a man rides a bicycle along Beirut's seaside Corniche, as Lebanese authorities warned of a new wave of the coronavirus disease (COVID-19) as the numbers jumped to the highest point in more than a month, after the government eased some restrictions on public life, in Beirut, Lebanon May 10, 2020. Picture taken May 10, 2020. REUTERS/Mohamed Azakir

People walk along Beirut's seaside Corniche, as Lebanese authorities warned of a new wave of the coronavirus disease (COVID-19) as the numbers jumped to the highest point in more than a month, after the government eased some restrictions on public life, in Beirut, Lebanon May 10, 2020. Picture taken May 10, 2020. REUTERS/Mohamed Azakir

Beriev A-50 early warning aircraft flies during a rehearsal for the flypast, which marks the 75th anniversary of the victory over Nazi Germany in World War Two, in Moscow, Russia May 4, 2020. The traditional large-scale Victory Day military parade across Red Square was postponed due to the outbreak of the coronavirus disease (COVID 19). REUTERS/Evgenia Novozhenina

A legal warning notice hangs at a protest camp surrounded by trees set to be felled to make way for Britain's HS2 high-speed railway project in ancient woodland in South Cubbington Wood near Leamington Spa, Britain, March 2, 2020. Picture taken March 2, 2020. REUTERS/Hannah McKay

Tennis players stand behind a warning band at the Smashing Suns tennis club as the government loosened a seven-week-old coronavirus lockdown due to the coronavirus disease (COVID-19) outbreak in Vienna, Austria May 2, 2020. Picture taken May 2, 2020. REUTERS/Leonhard Foeger

A news truck displays a social distancing warning as the global outbreak of the coronavirus disease (COVID-19) continues, in Los Angeles, California, U.S., May 1, 2020. REUTERS/Lucy Nicholson

A warning sign is shown at a closed beach park during the outbreak of the coronavirus disease (COVID-19) in Del Mar, California, U.S., April 30, 2020. REUTERS/Mike Blake

A coronavirus warning sign is reflected as self-proclaimed history buff Amitai Zuckerman from Maryland pays a visit to the Vietnam Veterans Memorial on the day when coronavirus deaths in the U.S. surpassed the 58,220 Americans killed in the Vietnam War, in Washington, U.S., April 29, 2020. REUTERS/Kevin Lamarque

Beside a coronavirus warning sign, a man takes a photo during a visit to the Vietnam Veterans Memorial on the day when coronavirus deaths in the U.S. surpassed the 58,220 Americans killed in the Vietnam War, in Washington, U.S., April 29, 2020. REUTERS/Kevin Lamarque

With a coronavirus warning sign nearby, self-proclaimed history buff Amitai Zuckerman from Maryland pays a visit to the Vietnam Veterans Memorial on the day when coronavirus deaths in the U.S. surpassed the 58,220 Americans killed in the Vietnam War, in Washington, U.S., April 29, 2020. REUTERS/Kevin Lamarque

Looking out the band office window at a newly raised M.A.S.H tent, where provincial nurses will test residents for coronavirus disease (COVID-19), idle warning signs sit in the remote First Nations community of Gull Bay, Ontario, Canada April 27, 2020. Picture taken April 27, 2020. REUTERS/David Jackson

A sign on highway 527 warns of restricted access for non residents to Gull Bay, a remote First Nations community in Ontario, Canada April 27, 2020. Picture taken April 27, 2020. REUTERS/David Jackson

Russian Air Force Beriev A-50 early warning aircraft and Sukhoi Su-27 jet fighter fly in Kaliningrad, Russia April 25, 2020. Picture taken April 25, 2020. REUTERS/Vitaly Nevar

Russian Air Force Beriev A-50 early warning aircraft and Sukhoi Su-27 jet fighters fly in Kaliningrad, Russia April 25, 2020. Picture taken April 25, 2020. REUTERS/Vitaly Nevar

Motorbikes drive past a billboard warning against the coronavirus disease (COVID-19) after the government eased nationwide lockdown during the outbreak in Ho Chi Minh, Vietnam, April 25, 2020. REUTERS/Yen Duong

A sign warning people about social distancing is seen outside closed beach huts during the coronavirus disease (COVID-19) outbreak, in Cromer, Britain April 24, 2020. REUTERS/Andrew Couldridge

A sign warning of the spread of the coronavirus disease (COVID-19) is seen in front of the closed Chicago Board of Trade in Chicago, Illinois, U.S., April 23, 2020. REUTERS/Shannon Stapleton

A farmer rides a bycycle past a poster warning about the coronavirus disease (COVID-19) outbreak in Hanoi, Vietnam April 22, 2020. REUTERS/Kham

People wearing face masks walk past a Uncle Sam sign warning people to stay home as the coronavirus disease (COVID-19) continues to spread, in Chicago, Illinois, U.S., April 21, 2020. REUTERS/Shannon Stapleton

A coronavirus warning sign is posted at a closed pedestrian crossing at the U.S.-Mexico border during the coronavirus disease (COVID-19) outbreak in San Diego, California, U.S., April 21, 2020. REUTERS/Mike Blake

A poster warning against the spread of 'fake news' online on the coronavirus disease (COVID-19) is seen on a street in Hanoi, Vietnam April 20, 2020. REUTERS/Kham

A poster warning about the coronavirus disease (COVID-19) is seen on a street in Hanoi, Vietnam April 20, 2020. REUTERS/Kham

A poster warning about the coronavirus disease (COVID-19) is seen on a street in Hanoi, Vietnam April 20, 2020. REUTERS/Kham

A poster warning about the coronavirus disease (COVID-19) is seen on a locked hotel in Hanoi, Vietnam April 20, 2020. REUTERS/Kham

A New York City worker puts out a sign at Hudson River Park in Manhattan's West Village warning people to social distance and wear a face covering, amid the spread of the coronavirus disease (COVID-19), New York, U.S., April 19, 2020. REUTERS/Michelle Nichols

A sign behind a fence warns residents that a lakeside promenade is closed due to health safety measures amid the coronavirus disease (COVID-19) outbreak, in Zurich, Switzerland April 17, 2020. REUTERS/Arnd Wiegmann

A sign behind a fence warns residents that a lakeside promenade is closed due to health safety measures amid the coronavirus disease (COVID-19) outbreak, in Zurich, Switzerland April 17, 2020. REUTERS/Arnd Wiegmann

A warning sign "Anyone who steals personal protective equipment endangers colleagues! Theft will be reported to the police" is seen in an elevator at a clinic in Bad Wildungen, Germany, April 16, 2020, as the spread of the coronavirus disease (COVID-19) continues. REUTERS/Kai Pfaffenbach

A woman wears a protective face mask as she walks past a poster warning about the coronavirus disease (COVID-19) outbreak in Hanoi, Vietnam April 15, 2020. REUTERS/Kham

Women pick silver hairs for each other on a lane near a poster warning about the coronavirus disease (COVID-19) outbreak, in Hanoi, Vietnam April 15, 2020. REUTERS/Kham

A man uses a smartphone as he walks past a poster warning against spreading 'fake news' on the coronavirus in Hanoi, Vietnam April 14, 2020. Picture taken April 14, 2020. REUTERS/Kham

Men wear protective masks as they walk past a poster warning against the spread of 'fake news' online on the new coronavirus in Hanoi, Vietnam April 14, 2020. Picture taken April 14, 2020. REUTERS/Kham

A warning sign is pictured outside the Monroe Correctional Complex, the site of a recent inmate protest after several inmates and staff tested positive for COVID-19, as efforts continue to help slow the spread of coronavirus disease (COVID-19) in Monroe, Washington, U.S. April 14, 2020. REUTERS/Jason Redmond

A mural warns residents of the danger of coronavirus disease (COVID-19) outbreak on the Navajo reservation, in Shiprock, New Mexico, U.S., April 8, 2020. Picture taken April 8, 2020. REUTERS/Andrew Hay

A road sign outside Bloomfield warns Navajos to stay home during their nation's 8pm to 5am curfew to slow the spread of the coronavirus disease (COVID-19), New Mexico, U.S., April 7, 2020. Picture taken April 7, 2020. REUTERS/Andrew Hay

A sign, warning the public not to trespass into the Quinault Indian Reservation, stands on the side of a road in Taholah, Washington, U.S., March 2, 2020. REUTERS/Stephanie Keith SEARCH ''QUINAULT CLIMATE CHANGE'' FOR THIS STORY. SEARCH ''WIDER IMAGE'' FOR ALL STORIES.

A sign is seen beside a road with warnings "Araf" and "Slow" in Bala as the spread of the coronavirus disease (COVID-19) continues, Bala, Gwynedd, Wales, Britain, April 11, 2020. REUTERS/Carl Recine

Digital signs warn residents and visitors to stay home days after Maryland Governor Larry Hogan imposed a stay-at-home order for all Maryland residents, following the outbreak of coronavirus disease (COVID-19), in Annapolis, U.S., April 8, 2020. REUTERS/Mary F. Calvert

Digital signs warn residents and visitors to stay home days after Maryland Governor Larry Hogan imposed a stay-at-home order for all Maryland residents, following the outbreak of coronavirus disease (COVID-19), in Annapolis, U.S., April 8, 2020. REUTERS/Mary F. Calvert

Biohazard warning signs are placed on the coffins of people who died of the coronavirus disease (COVID-19), at a mortuary near the city of Charleroi, Belgium April 7, 2020. REUTERS/Yves Herman

Biohazard warning signs are placed on the coffins of people who died of the coronavirus disease (COVID-19), at a mortuary near the city of Charleroi, Belgium April 7, 2020. REUTERS/Yves Herman

A biohazard warning sign is placed on a coffin of a person who died of the coronavirus disease (COVID-19), at a mortuary near the city of Charleroi, Belgium April 7, 2020. REUTERS/Yves Herman

Biohazard warning signs are placed on the coffins of people who died of the coronavirus disease (COVID-19), at a mortuary near the city of Charleroi, Belgium April 7, 2020. REUTERS/Yves Herman