Ukrainian President Viktor Yushchenko (L) and Prime Minister Yuri Yekhanurov (R) stand outside the "Chernobyl church" in Kiev during a service of remembrance for those who fought the fire at the Chernobyl nuclear power plant in 1986, April 26, 2006. Mourners marked the 20th anniversary of the nuclear disaster on Wednesday, honouring those who died as leaders pledged to ensure it would never happen again. REUTERS/Ivan Chernichkin