The U.S., France and Britain on Monday stepped up pressure on Syrian President Bashar Assad to stick to a deal under which Syria must give up its chemical weapons and warned he would suffer consequences if Damascus did not comply.
Russia immediately cautioned against imposing tough penalties on the Syrian leader, while in Syria itself fighting was reported on several fronts, and a monitoring group stated that a government helicopter had been brought down.
The three Western permanent members of the United Nations Security Council said they would seek a strong resolution in the forum, setting binding deadlines for the removal of Syria's chemical weapons, French President Francois Hollande's office said.
The statement followed talks in Paris, two days after the U.S. reached a deal with Assad's ally Russia on chemical weapons that could avert U.S. strikes on Syria as punishment for a chemical attack in Damascus last month.
U.S. Secretary of State John Kerry told a news conference in Paris that the three powers agreed with Russia that Assad must suffer consequences if he fails to comply with UN demands.
"If Assad fails in time to abide by the terms of this framework, make no mistake, we are all agreed — and that includes Russia — that there will be consequences," Kerry said.
The accord offered the Syrian leader "no lifeline" and he had "lost all legitimacy," Kerry added.
After Hollande met Kerry and British Foreign Secretary William Hague and their French counterpart Laurent Fabius, an aide to Hollande said: "The idea is to stick to a firm line."
"They've agreed to seek a strong and robust resolution that sets precise and binding deadlines with a calendar," said the official, who spoke on condition of anonymity.
Russia accused the Europeans of trying to re-interpret the agreement.
Speaking in Moscow, Foreign Minister Sergei Lavrov said any rush to draw up a resolution threatening to punish Syria in the event of noncompliance showed a "lack of understanding" of the agreement reached for Assad to give up his chemical weapons.
"Our [European] partners want to again unilaterally review what we've agreed on with the Americans. That's not how you do business, and I'm sure that despite these statements that are coming from European capitals, the Americans will, as proper negotiators, strictly stick to what has been agreed on," Lavrov said.
Peace Talks Plan
He also said it might be time to consider efforts to force the Syrian opposition to attend an international peace conference instead of just urging them to do so. So far, the rebels have said they would not attend talks if the Syrian president was there too.
The deal reached in Geneva put off the immediate threat of airstrikes, and Lavrov stressed at the time that it did not include any automatic use of force in the event of Syria's failure to comply. But U.S. President Barack Obama said force remained an option if Assad reneges.
Syria's government at the weekend hailed the Russian-brokered deal as a "victory," while rebels who have been fighting Assad's forces since 2011 say the deal has benefited their enemy in the civil war.
Assad briefly dispersed his forces to protect them from strikes threatened by the U.S. in response to the chemical weapons attack on Aug. 21 that Washington claimed killed more than 1,400 people, many of them children.
Opposition voices say the chemical weapons deal effectively gives Assad permission to carry on with his conventional war, in which 120,000 people have died so far.
Fighting between rebels and government forces, which often kills more than 1,000 people a week, ground on from the outskirts of Damascus to the central Hama province to Deir al-Zor in the east.
In the coastal province of Latakia, a government helicopter that was dropping barrels filled with explosives in the Jebel Akrad region was downed, although it was not immediately clear how, according to the Syrian Observatory for Human Rights, an anti-Assad monitoring group based in Britain.
Government warplanes also hit targets in the Sbeneh area south of Damascus and in the eastern Deir al-Zor province, according to the Observatory, which has a network of sources across Syria.
The rebels have struggled to counter Assad's air power, but Western countries have been wary of supplying them with sophisticated anti-aircraft weapons that they fear may end up in the hands of anti-Western Islamist factions.
The Syrian government has told the UN it would adhere to a treaty banning chemical weapons. The U.S.-Russian framework agreement calls for the UN to enforce the removal of existing stockpiles by the middle of next year.
Assad has less than a week to begin complying with the deal by handing over a full account of his chemical arsenal. He must allow UN-backed inspectors from the Hague-based Organization for the Prohibition of Chemical Weapons, or OPCW, to complete their initial on-site checks by November.
Assad told Russian state television last week that his cooperation was dependent on an end to threats of war and to U.S. support for rebel fighters. But it seems likely that Moscow can prevail on getting him to comply, at least initially, with a deal in which it has invested considerable personal prestige.
Experts say the removal of up to 1,000 tons of chemical agents will be highly problematic in the middle of Syria's civil war, although they assume that the dozens of chemical weapons sites remain under government control.
"The OPCW just doesn't have the manpower to man such an operation like this, so they would bring in other experts," former OPCW official Dieter Rothbacher said. "Moving an entire stockpile is something that has never been done before. It is unprecedented."
He estimated that even in normal circumstances it would take a team of 15 to 20 inspectors several months to take an inventory and verify Syria's stockpile.
The UN Commission of Inquiry on Syria said Monday that it was investigating 14 alleged attacks with chemical weapons or chemical agents in Syria over the last two years.
UN human rights investigators also said hardline Syrian rebels and foreign fighters invoking jihad, or holy war, had stepped up killings, executions and other abuses in the north since July.
There were now a number of brigades made up entirely of non-Syrians, underlining how the 2 1/2-year-old conflict has pulled in neighboring countries and widened sectarian faultlines across the region.
"The point is that these extreme elements have their own agenda and certainly not a democratic agenda that they are seeking to impose," investigator Vitit Muntarbhorn said.