Major international powers meeting in Paris have called a UN-backed peace plan the "last hope" to resolve the Syrian crisis, but warned they are ready to consider "other options" if UN-Arab League mediation efforts led by Kofi Annan break down.
The meeting on Thursday resolved that the "Friends of Syria" group, which includes France, the United States, Saudi Arabia and Qatar, would do everything to ensure the Arab League-UN plan succeeded.
"Every day that passes means tens of new Syrian civilian deaths," said Alain Juppe, the French foreign minister, as he read out the conclusions of the meeting.
"It is not time to prevaricate. It is time to act. Though fragile, the Annan mission represents a last hope," the statement said.
"If this were not to happen ... the UN Security Council and international community would have to look at other options."
The group said it wanted the UN observers in Syria to be given all the "necessary means" to complete their mission, including having all modern equipment that would enable them to ensure efficient surveillance.
A team of seven monitors are currently on the ground in Syria and the UN wants to see up to 300 observers deployed for a three-month mission.
The 14 nations said they were concerned by the worsening humanitarian situation and its impact on neighbouring countries and were committed to providing humanitarian aid in all forms.
Arms embargo call
US Secretary of State Hillary Clinton also called for the UN Security Council to adopt a global arms embargo and other tough measures against Syria to reinforce existing Western embargoes if the country fails to abide by the UN plan.
Clinton stopped short of calling for outside military intervention in Syria but said it was time to impose more consequential measures on Syrian President Bashar al-Assad's regime.
"We have to keep Assad off balance by leaving options on the table,'' she told the conference.
"We need to continue to work and move toward a Security Council authorisation so that we have the authority to proceed when the times are right," she said.
"We need to start moving very vigorously in the Security Council for a Chapter 7 sanctions resolution, including travel, financial sanctions, an arms embargo, and the pressure that that will give us on the regime to push for compliance with Kofi Annan's six-point plan," she said.
Russia said it was staying away because the talks were only aimed at isolating the regime and would hurt the chances of direct peace talks.
The meeting came hours after Syria and the UN signed a deal on the framework for international observers to monitor the nation's shaky ceasefire between government forces and opposition fighters.
The Syrian foreign ministry said "this agreement comes within the framework of Syrian efforts aimed at making the Annan plan succeed and to facilitate the UN observer mission while respecting Syria's sovereignty".
Ahmad Fawzi, the spokesman for Annan, said in Geneva that discussions had begun with members of the Syrian opposition to ensure they would also comply with the ceasefire.
"The hard part lies ahead, a truly Syrian-led and -owned political dialogue to address the legitimate concerns and aspirations of the Syrian people," he said.
Ban Ki-moon, the UN chief, has said he wants 300 unarmed observers sent on a three-month mission. He has also insisted that the Assad's regime adhere to the peace plan.
The 300 observers would be deployed over several weeks and work across the country.
Their job will be to monitor the ceasefire that was supposed to take hold on April 12 and the implementation of the Annan plan, to which Syria has committed itself.
Ban said the proposed mission would "greatly contribute to observing and upholding the commitment of the parties to a cessation of armed violence in all its forms".
Diplomats said a resolution allowing the full observer mission could be ready early next week if there was agreement by the UN Security Council.
The latest diplomatic developments came as an opposition activist network on Thursday reported the deaths of three people in the central city of Homs as troops shelled rebel-held areas in the central city and the nearby town of al-Quseir.
The Local Co-ordination Committees (LCC) also said that three people were killed in the Damascus suburb of Yabroud amid heavy gunfire by government forces.
In-depth coverage of escalating violence across Syria
Deaths were also reported in clashes between troops and army defectors in Deir al-Zor in the east.
Thursday's clashes in the eastern city have reportedly left three others wounded.
Three more people were killed in the northwestern province of Idlib, the LCC reported.
The UN says well over 9,000 people have been killed in Syria since an uprising against Assad broke out in March 2011.
Ban on Thursday said Damascus failed to adhere to the ceasefire as activists reported the deaths of scores since the truce started on April 12.
Below is a copy of the agreement between Syria and the UN signed on Thursday. It lays out the framework for the monitoring mission and spells out the requirements of the Syrian government and opposition under the six-point peace plan.