German Foreign Minister Guido Westerwelle announced on Tuesday that Germany was adding its name to a growing number of countries who were taking action to expel Syrian ambassadors. Britain, France, Italy, Spain, Australia and Canada all said they were expelling top diplomats from their capitals in protest against Friday's massacre in Houla.

"Germany is acting with its partners," Westerwelle said in a statement. "We are aiming to ensure that our unmistakable message does not fall on deaf ears in Damascus." He gave the 52-year-old ambassador to Germany 72 hours to leave the country.

Germany's foreign minister went on to reiterate calls for Assad to step down, urging the UN Security Council to reconsider its stance on Syria.

"The Syrian regime is responsible for the terrible actions in Houla. Whoever there or elsewhere, violates the UN Security Council resolution by using heavy weapons against their own people must bear serious diplomatic and political consequences."

"We will push for a new engagement by the UN Security Council over the situation in Syria," Westerwelle added.

The UN had previously said that 108 people, including 49 children, were killed in Houla on Friday.

Victims 'summarily executed'

The UN-Arab League special envoy to Syria, Kofi Annan, met Assad on Tuesday as further details on Friday's killings in Houla began to emerge.

Rupert Colville, a spokesman for the UN High Commissioner for Human Rights, delivered preliminary results of an investigation into the massacre.

"It's believed that under 20 of the 108 killings can be attributed to artillery and tank fire," Colville told reporters in Geneva.

"Most of the rest of the victims were summarily executed in two separate incidents," Colville said. "At this point it looks like entire families were shot in their houses."

Colville said this information was based on accounts gathered from survivors by UN monitors.

The witnesses had blamed pro-government militia gangs known as shabiha for carrying out the attacks, saying these Assad loyalists sometimes operated "in concert" with government forces.

Annan demands end to violence

Annan's spokesman Ahmad Fawzi issued a statement shortly after the talks with Assad concluded on Tuesday, saying the former UN secretary general had conveyed the international community's "grave concern" over the enduring violence in Syria, "in particular the recent events in Houla.

"[Annan] conveyed in frank terms his view to President Assad that the six-point plan cannot succeed without bold steps to stop the violence and release detainees, and stressed the importance of full implementation of the plan," Fawzi said.

Among the terms of Annan's roadmap for peace, Syrian forces agreed to cease using artillery fire and withdraw troops from towns and cities.

msh, ccp/ng (AFP, AP, Reuters)