Syria has been given a week to declare its full array of chemical weapons under the terms of an agreement between Russia and the United States.
The brokered deal demands that Syria's president Bashar Assad consents to international inspections within a few months and the full destruction of the weapons within a year.
But US President Barack Obama has warned that military force remains an option if the timetable is not kept.
ITV News' International Editor Bill Neely reports from Damascus:
"If diplomacy fails, the United States remains prepared to act," Mr Obama said. "The international community expects the Assad regime to live up to its public commitments."
His Secretary of State, John Kerry, unveiled the plan alongside Russian Foreign Minister Sergei Lavrov following three days of talks in Geneva.
He said Assad must produce a "comprehensive listing" of its chemical weapons within a week.
How feasible an inspection and disarmament of the still secret stockpile amid Syria's ongoing civil war remains unknown.
Mr Kerry said the accord required "ambitious" targets but appeared confident they could be met. The goal is to complete destruction of Syria's arsenal in the first half of 2014.
The deal, though, was a blow to Assad's opponents who hoped Mr Obama's public endorsement of military strikes on the Assad regime in response to a gas attack on rebel territory two weeks ago could prove decisive in the civil war.
Mr Kerry and Mr Lavrov said they hoped the weapons agreement could herald broader peace talks.
The United Nations said it has received all the documents necessary for Syria to join the chemical weapons convention and the country will come under the treaty next month.