Israelis take cover as a siren warning of incoming rockets sounds in the Israeli-occupied Golan Heights, near the ceasefire line between Israel and Syria June 17, 2015. Israel signaled readiness on Tuesday to intervene if Syrian refugees were to throng to its armistice line on the Golan Heights, after Israel's Druze Arab minority stepped up a public campaign to help brethren caught up in the civil war next door. REUTERS/Baz Ratner