Major Western powers said Tuesday they would expel Syria's diplomatic envoys in protest at the weekend massacre in the town of Houla, in which more than 100 people were killed.
Britain, France, Germany, Italy and Spain as well as Canada and Australia announced decisions to expel ambassadors or top envoys, and British Foreign Secretary William Hague said the United States would do the same.
The coordinated move followed mounting international outrage over the massacre in the central town of Houla, in which at least 108 people, including 49 children, were killed.
Hague said the expulsion of the top Syrian diplomat in London, charge d'affaires Ghassan Dalla, and two other envoys would send a "stark message" that time was running out for Syrian President Bashar al-Assad.
The move was part of the increased pressure by the international community on senior figures in the regime to "get the message across to them that they have to choose, that time will run out for Assad," Hague said.
"As part of that pressure today we have again called the Syrian charge d'affaires in London here to the Foreign Office. He has been given seven days to leave the country," Hague said.
"Our allies and partners around the world will be taking similar action and announcing it today -- including France, Germany, Italy, Spain, the United States, Canada and Australia."
Syria had already withdrawn its ambassador from London.
Canada said it was expelling every Syrian diplomat in the capital.
"Today, Canada is expelling all Syrian diplomats remaining in Ottawa. They and their families have five days to leave Canada," Foreign Affairs Minister John Baird said in a statement.
German Foreign Minister Guido Westerwelle said: "We are aiming to ensure that our unmistakable message does not fall on deaf ears in Damascus."
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In Paris, President Francois Hollande told journalists that France's decision to expel Ambassador Lamia Shakkur, which would be formally communicated to her on Tuesday or Wednesday, came amid talks with Britain, Russia and the UN on the next steps to take in the Syria crisis.
"I had a conversation yesterday with David Cameron, the British prime minister. Laurent Fabius, the (French) foreign minister, had a discussion with the secretary general of the United Nations and we agreed on a number of ways to put pressure on Syria," he said.
"We're also in talks with Russia, which plays a role, and I will meet with President (Vladimir) Putin on Friday."
Putin, whose country has vetoed UN resolutions on the Syria crisis but has sought to distance itself from the regime following the Houla slaughter, is due in France on Friday.
He and Hollande are scheduled to meet for a working dinner that evening.
Hollande also announced that Paris would host a new meeting of the Friends of Syria group in early July.
Meanwhile Fabius, France's new foreign minister, forcefully condemned Assad and called for his departure in an interview published Tuesday.
"Assad is the murderer of his people. He must leave power... the sooner the better," Fabius told Le Monde newspaper, echoing the views of the previous right-wing administration of former president Nicolas Sarkozy.
"If Bashar al-Assad falls, who will replace him? We need to find a credible political transition involving the departure of Bashar al-Assad while avoiding any 'Iraqisation' of the country," he said.
But he ruled out supplying the Syrian opposition with arms.
"We're certainly not there," he said when asked about the possibility.
"No state is willing to consider today a ground operation" in Syria. "The risks of regional extension would be formidable, especially in Lebanon."