UK Foreign Secretary William Hague insists the world must hold Syria to account if the Assad regime fails to comply with an international proposal to destroy its chemical weapons.
Mr Hague said the UK's first priority was to secure prompt action at the UN Security Council that enshrines in a resolution the Syrian regime's responsibility to hand over its chemical weapons stocks.
He added the resolution should create a binding commitment for the regime to give up its weapons within a specific time-frame and to "credibly, reliably and promptly" place them under international control for destruction.
The Foreign Secretary was speaking after a meeting in Paris where US secretary of state John Kerry briefed Mr Hague and French foreign minister Laurent Fabius on his deal with Russia for the international community to take control of President Bashar al Assad's chemical weapons.
Under the agreement hammered out between Mr Kerry and Russian foreign minister Sergei Lavrov in Geneva, the regime is required to submit a full inventory of its chemical stockpile by the end of the week, allow international inspectors into the country by November, and complete the surrender of its arsenal by mid 2014.
Mr Hague said today: "It is the Assad regime that has stockpiled these weapons and that has used them repeatedly against the Syrian people.
"So the pressure is on them to comply with this agreement in full. The world must be prepared to hold them to account if the don't and our three countries are certainly determined to do so."
UN secretary general Ban Ki-moon said last week that he believed it would be "an overwhelming report" showing that chemical weapons were used.
Mr Ban - who was apparently unaware that his comments were being broadcast on UN television - also said that the Assad regime had "committed many crimes against humanity."
Mr Hague added that the allies are in agreement that the "credible threat of military force" played a role in bringing about an opening in relation to Syria.
Mr Hague said the UK, US and France would use their "full weight" as permanent members of the UN Security Council to get the chemical weapons out of Syria and bring about a peaceful end to the brutal civil war.
He said: "We are determined to do everything we can to stop the bloodshed in Syria, to support the moderate opposition and to alleviate humanitarian suffering.
"Our goal remains to convene a second Geneva conference to bring all sides together to agree a political solution to the conflict and we will work with Russia on bringing that about as soon as possible.
"In that regard I welcome the (Syrian) National Coalition's decision to appoint an interim prime minister - Ahmed Tohme.
"There can be no peaceful settlement in Syria without the legitimate Syrian opposition.
"So the task ahead is very difficult and complex but our three countries are united and determined to use our full weight as permanent members of the United Nations Security Council and as each other's close allies to implement the agreement on Syria's chemical weapons, to maintain the pressure on the Assad regime, and to bring about a peaceful end to this appalling conflict."
Mr Kerry said it was clear that Assad has lost all legitimacy and stressed the need for a strong, forceful UN resolution that Assad complies with.
If the Assad regime did not take the resolution seriously it would "play games", he said.
Mr Kerry said all the countries involved, including Russia, were agreed that if Assad fails to comply "there will be consequences".
He said: "What we achieve in this agreement as we translate the Geneva agreement into a United Nations resolution has to be strong and it has to be forceful, it has to be real, it has to be accountable, it has to be transparent, it has to be timely.
"All of those things are critical and it has to be enforced. If the Assad regime believes that this is not enforceable that we are not serious they will play games."
He went on: "We will not tolerate avoidance or anything less than full compliance by the Assad regime to the core principles of what has been achieved here.
"If Assad fails to comply with the terms of this framework, make no mistake, we are all agreed, and that includes Russia, that there will be consequences.
"The framework fully commits the United States and Russia to impose measures under chapter seven of the UN charter in the event of non-compliance.
"President Obama and I have repeated his statement, have warned that should diplomacy fail the military option is still on the table."
Mr Kerry said the end strategic goal remained a transitional Syrian government that would lay the path for a new Syria.
He said he understood that removing chemical weapons would still leave Assad with the other weapons of war and so the allies would do everything they could to push for a political solution.
Mr Kerry said: "We make it clear that Assad has lost all legitimacy to be possible to govern this country and we remain committed to the opposition and committed to the Geneva process which calls for a transition government with full executive authority by mutual consent of the parties that will lay out the structure for the new Syria.
"That's our end strategic goal here and all of us remain committed to that goal and committed to ending the violence as soon as possible.
"We understand that removing the chemical weapons still leaves him with artillery and airplanes and he sues them indiscriminately against his people and we are going to do everything in our power to continue to push towards the political resolution that is so critical to ending that violence."