An international chemical weapons watchdog said on Saturday that it has begun examining the details of Syria's chemical weapons, which were submitted by Syria, while U.S. officials have expressed surprise over the “completeness” of the submission.  

The Syrian government handed over a preliminary disclosure of the chemical weapons it possesses to the Organization for the Prohibition of Chemical Weapons, or OPCW, on Friday. The U.N.-backed watchdog, which is overseeing the dismantling of Syria’s chemical arsenal, said that details of the declaration are “now being examined by the Technical Secretariat of the Organization.”

According to the OPCW officials, the initial list submitted by Bashar Assad’s regime was "quite long,” Reuters reported.

U.S. officials cited by The New York Times said that Washington was encouraged by the initial disclosure made by the Syrian government.

“We were pleasantly surprised by the completeness of their declaration,” an official, who declined to be identified because he was not authorized to speak publicly on the matter, told the Times. “It was better than expected,” he added.

The submission was made within the first deadline, which had been set by an agreement between the U.S. and Russia at Geneva last Saturday, in a bid to thwart a possible U.S. military strike on Syria to punish the Assad’s regime for allegedly killing more than 1,400 people in an Aug. 21 attack, near Damascus.

According to the framework, Syria had to disclose its complete chemical-weapons stockpile within one week and give United Nations inspectors unfettered access to all of its chemical weapons ahead of eliminating them, in nine months.

A Western diplomat on Friday said that any lapse from the Syrian government in disclosing its complete chemical arsenal could result in world powers seeking immediate punitive action against it, at the U.N. If Assad’s regime failed to comply with the terms of disclosure, then "this matter is going to go straight to the Security Council," the official quoted by Reuters warned.

Syria has until Saturday to provide complete details of its chemical weapon stockpile and to disclose all the facilities for developing its chemical agents and weapons. Both Russia and the U.S. agreed that Syria has about 1,000 tons of poisonous agents, including sarin and mustard gas.

A U.N. report released on Monday confirmed that the nerve agent sarin was used in the Aug. 21 attack in the Ghouta area, near Damascus. Assad’s regime and its staunch ally Russia claim rebel forces carried out the attack, while U.S. and other Western powers including France and the U.K. blame Assad’s government for the chemical strike.

The OPCW’s 41-member Executive Council, which is scheduled to meet early next week, has to review the inventory submitted by Syria and agree to implement the U.S.-Russia deal to dismantle Syria’s chemical weapon stockpile. After that, the U.N. will endorse the U.S.-Russia brokered deal through a resolution, Reuters reported.