Syrian diplomat expelled,The US has joined Britain, France, a host of other EU countries, Australia and Canada in expelling Syrian diplomats in a chorus of global outrage at the massacre of more than 100 people, including scores of children, in Houla.

On a day when the UN reported that many of those killed at the weekend had been shot at close range, France's president François Hollande told French television that military intervention could not be ruled out but had to be backed by the UN security council.

The UN and Arab League's special envoy, Kofi Annan, who was in Damascus for talks with president Bashar al-Assad, described the situation as a "tipping point".

"The Syrian people do not want the future to be one of bloodshed and division. Yet the killings continue and the abuses are still with us today." Annan said. "As I reminded the president, the international community will soon be reviewing the situation."

Syria has denied responsibility for the atrocity, calling it a "terrorist massacre".

The Syrian National Council, the main exiled opposition group, welcomed the diplomatic expulsions as an "essential part of the response to the horrific massacres the regime is carrying out".

But it also called for a UN security council resolution authorising the "use of force" under chapter VII of the UN charter – the kind that paved the way for the Nato-led intervention in Libya last year.

There is no evidence that that is likely to be agreed. The White House said it did not believe military intervention in Syria was the right course of action as it would "lead to more carnage".

It is also far from certain that angry words from across the world and Syria's growing international isolation would have any effect on a regime that is fighting for its survival and is still supported by its principal ally, Russia.

The swiftly but clumsily co-ordinated diplomatic action came as Kofi Annan, representing the UN and the Arab League, met a defiant Assad in the Syrian capital, Damascus, "to convey the grave concern of the international community about the violence in Syria". Yet there was no sign of improved prospects for the implementation of Annan's apparently failing six-point peace plan.

During their talks, Assad complained to Annan about escalating attacks by "armed terrorist groups" and urged unnamed countries to stop "financing, arming and harbouring them," Syria's Sana news agency reported. It did not report on the latest orchestrated moves against Damascus. Qatar, Saudi Arabia, Turkey and the US have all been accused by Syria of backing the rebels.

The prime minister of Qatar, Hamad bin Jassim Al Thani said in Doha that the Annan plan had already failed since none of its six points had been implemented.

Germany, Spain, Italy and Bulgaria also announced they were expelling Syria's ambassadors. The Netherlands declared the Syrian envoy "persona non grata" but said he would not be expelled because he is also Syria's ambassador to Belgium. It was not immediately clear why other members of the 27-member EU had not joined in.

The Syrian charge d'affaires in the US, Zuheir Jabbour, has been given three days to leave the country. "We hold the Syrian government responsible for this slaughter of innocent lives," said the state department spokeswoman, Victoria Nuland. "This massacre is the most unambiguous indictment to date of the Syrian government's flagrant violations of its UN security council obligations."

Syria withdrew its ambassador from Washington in December after the US closed its embassy in Damascus, along with Britain and France, over the violent crackdown against opponents of the Assad regime, which has cost an estimated 15,000 lives over the last 15 months.

William Hague, Britain's foreign secretary, said the expulsions aimed to tell Assad and those around him that time was running out for them to comply with Annan's plan. "The world, the international community, is appalled by the violence that has continued, by the behaviour of the regime, by the murder of so many innocent people, including in the terrible massacre at Houla," he said.

The UN said that most of the 108 victims of the Houla massacre were shot at close range, including women, children and entire families gunned down in their homes. Survivors and witnesses cited by the UN blamed the house-to-house killings on pro-government thugs known as shabiha. Rupert Colville, spokesman for the UN high commissioner for human rights, said: "What is very clear is this was an absolutely abominable event that took place in Houla, and at least a substantial part of it was summary executions of civilians, women and children. At this point, it looks like entire families were shot in their houses."

Hollande was the first European leader to announce the expulsion of a Syrian ambassador, describing it as "not a unilateral decision but in consultation with our partners". But there was irritation in London that Paris made the announcement without waiting for other countries.

The US announcement came later because protocol required that the US state department first call in Jabbour before making the move public.

As Britain had already effectively closed its Damascus embassy on security grounds earlier this year and Syria's ambassador, Sami Khiyami, left London some months ago, so the expulsion is largely symbolic. The charge d'affaires, Ghassan Dalla, was given the news when he was called into the Foreign Office. Two other Syrian diplomats have also been told to leave the UK.

Anti-Assad Syrians were sceptical about the move. "Don't jump to conclusions about expulsions of Syrian ambassadors," tweeted the commentator Rime Allaf. "It's symbolic; doesn't mean intervention at all!"

Ausama Monajed, a member of the SNC, said: "The expulsion of the Syrian ambassadors is proof that members of the international community know who is the butcher and killer in Syria, and who is responsible for inciting violence and pushing the country into a civil war. This is a proof that Annan plan will never work in this conflict. Mediation, negotiation and political solutions are alien to Assad."

source: guardian