Cairo: An Arab League committee has given Syria 24 hours to agree to allow an observer mission into the country or it could face sanctions.
Thursday's threat comes as international pressure mounts on President Bashar Assad to stop the brutal crackdown on an uprising against his regime. The UN says 3,500 people have been killed in the crackdown since March.
The Cairo-based Arab League called on Damascus to agree to an observer mission by Friday. If they refuse, the League will meet Saturday to decide on sanctions that could include stopping flights to Syria, ending financial dealings with Damascus and freezing Syrian assets.
The European Union said Thursday that protecting civilians caught up in Syria's crackdown on anti-government protests "is an increasingly urgent and important aspect" of responding to the bloodshed there. At least three more people were killed by Syrian security forces.
Syrian President Bashar Assad is under increasing international pressure to stop the brutal crackdown on an uprising against his regime that the UN says has left more than 3,500 people dead since it began in mid-March.
The Arab League suspended Syria's membership over the bloodshed and Syria's failure to abide by an Arab peace plan it signed.
Amid the diplomatic efforts, violence continued, with intense clashes reported between troops and army defectors near the town of Rastan in the restive central province of Homs, which has been one of the most volatile regions throughout the uprising
The British-based Syrian Observatory for Human Rights and the Local Coordination Committees said 15 defectors were either killed or wounded in the clashes.
Both groups also said that security forces killed at least three others in the provincial capital of Homs and the town of Houla near the border with Lebanon.
"Protection of civilians in Syria is an increasingly urgent and important aspect of responding to the events in country," Maja Kocijancic, an EU spokeswoman, said in a statement.
But the 27-nation bloc stopped short of endorsing French Foreign Minister Alain Juppe's call for EU-backed humanitarian corridors to allow aid groups a way in.
Juppe called the situation in Syria "no longer tenable" and accused Assad's regime of "repression of a savagery we have not seen in a long time."
He told France-Inter radio he was in contact with partners in the United Nations, U.S. Secretary of State Hillary Rodham Clinton and the Arab League about the possibility of setting up the humanitarian corridors.
Juppe suggested that aid groups such as the Red Cross could use the corridors to bring medical supplies to cities such as Homs.
Juppe first made the proposal after meeting with the leader of the opposition Syrian National Council on Wednesday.
France, Syria's one-time colonial ruler, was the first country to formally recognize Libya's opposition early in Muammar Gaddafi's crackdown on protests, and France played a prominent role in the NATO-led campaign of airstrikes against Gaddafi's forces.
Last month, Russia and China vetoed a Western-backed UN Security Council resolution condemning the bloodshed in Syria. They have argued that NATO misused a previous UN measure authorizing the use of force to protect civilians in Libya to justify months of air strikes and to promote regime change.
They expressed fears that any new resolution against Syria might be used as a pretext for a similar armed intervention.
First Published: Thursday, November 24, 2011, 08:45