AMSTERDAM, Dhu-AlQa'dah 15, 1434, Sep 21, 2013, SPA -- Syria has handed over information about its chemical arsenal to a U.N.-backed weapons watchdog, meeting the first deadline of an ambitious disarmament operation that averted the threat of Western air strikes, Reuters reported. The Organisation for the Prohibition of Chemical Weapons (OPCW) said on Saturday it had "received the expected disclosure" from Damascus, 24 hours after saying it had been given a partial document from Syrian authorities. It said it was reviewing the information, handed over after President Bashar al-Assad agreed to destroy Syria's chemical weapons in the wake of a sarin gas strike in Damascus's suburbs last month - the world's deadliest chemical attack in 25 years. Washington blamed Assad's forces for the attack, which it said killed more than 1,400 people. Assad blamed rebels battling to overthrow him, saying it made no sense for his forces to use chemical weapons when they were gaining the upper hand and while U.N. chemical inspectors were staying in central Damascus. The timetable for disarmament was laid down by U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov a week ago in Geneva when they set aside sharp differences over Syria to address the chemical weapons issue. Their plan set a Saturday deadline for Syria to give a full account of the weapons it possesses. Security experts say it has about 1,000 tonnes of mustard gas, VX and sarin - the nerve gas U.N. inspectors found had been used in the Aug. 21 attack. The U.S. State Department said on Friday, after the OPCW announced Syria's initial declaration, that it was studying the material. "An accurate list is vital to ensure the effective implementation," spokeswoman Marie Harf said. However, the two powers are divided over how to ensure compliance with the accord. U.S. President Barack Obama has warned that he is still prepared to attack Syria, even without a U.N. mandate, if Assad reneges on the deal. Russia, which says it is not clear who was behind the Aug. 21 attack and has a veto in the Security Council, opposes attempts by Western powers to write in an explicit and immediate threat of penalties under what are known as Chapter VII powers. It wants to discuss ways of forcing Syrian compliance only in the event that Damascus fails to cooperate. But a senior Russian official suggested on Saturday that if there were clear indications that Assad were not committed to handing over chemical weapons, Moscow may stop supporting him. "I'm talking theoretically and hypothetically, but if we became sure that Assad is cheating, we could change our position," said Sergei Ivanov, chief of staff for President Vladimir Putin. Ivanov said it would take two to three months to decide how long it would take to eliminate Syria's chemical weapons, a task that the Kerry-Lavrov agreement aims to complete by mid-2014. -- SPA 20:38 LOCAL TIME 17:38 GMT www.spa.gov.sa/1149172