Foreign Minister Avigdor Liberman said on Tuesday forces loyal to Syrian President Bashar Assad were responsible for an attack on Sunday that killed an Israeli boy on the Golan Heights.An anti-tank missile fired from Syria across the frontier fence killed Mohammed Qaraqara, 13, drawing Israeli tank fire and air strikes on Syrian army positions, which killed three Syrian soldiers. "We got all the analysis, all the intelligence and it was clear it was Syrian authorities, Assad's forces, who fired on the Israeli boy ... and they must pay the price," Liberman told Israel Radio. "I hope Damascus got the message," he said.It was the first time an Israeli official had said who perpetrated the attack, which Israel had earlier described as intentional and the most serious on the frontier since the start of the three-year-old Syrian conflict.The Syrian army has a presence on the Golan Heights but many areas are controlled by rebels, including militant groups hostile to Israel. "I think Israel responded exactly as we should have, in this case and all others. We cannot just gloss over an Israeli citizen, a boy, being murdered in cold blood with no one being held responsible," Liberman said.The Syrian conflict has spilled over into bordering countries and escalated regional tensions. Shelling from Syria has occasionally hit the Golan, including what Israel has said were deliberate attacks on its troops.