UN inspectors left their hotel in Damascus on Monday morning and began heading to the site of an alleged chemical weapons attack which left 355 people dead and many more injured in a nearby suburb last week. The Syrian government resisted inspection requests, but finally authorized the visit on Sunday.

Meanwhile, several mortar shells hit central Damascus, injuring at least three people, according to Syrian state news agency SANA. The state media said the Syrian opposition had been responsible for the attack on the district close to the UN inspectors' hotel.

But the United States and its allies say evidence has been destroyed by government shelling of the area over the past five days, and the Syrian offer to allow inspectors has come too late. There have been calls for military action to punish the world's worst, apparent, chemical weapon attack in 25 years.

The White House said on Sunday that President Barack Obama and French President Francois Hollande "discussed possible responses by the international community."

Syria and its allies

Syria's information minister said on Sunday that any US military action would "create a ball of fire that will inflame the Middle East."

Assad's closest ally Iran said the United States should not cross a "red line" by attacking Syria.

The Russian Foreign Ministry drew a parallel between reports Syrian President Bashar al-Assad's forces had used chemical weapons and Washington's 2003 intervention in Iraq following accusations by then-President George Bush's administration that Iraqi leader Saddam Hussein's government possessed weapons of mass destruction.

"We once again decisively urge [the United States] not to repeat the mistakes of the past and not to allow actions that go against international law," the Russian Foreign Ministry said on Sunday.

"Any unilateral military action bypassing the United Nations will ... lead to further escalation [in Syria] and will affect the already explosive situation in the Middle East in the most devastating way," the ministry added.

"The threat to use force against the Syrian regime sends the [Syrian] opposition conflicting signals," the ministry said. "All sponsors of the opposition, which have influence over it, must seek the fastest possible agreement from Bashar al-Assad's opponents to hold talks."

Germany and Britain

British Prime Minister David Cameron's office said that he had on Sunday spoken to German Chancellor Angela Merkel about the crisis: "The prime minister called Chancellor Merkel to discuss how the international community should respond to the chemical weapons attack in Syria last week," a Downing Street statement said.

"They agreed that this was a very grave incident and that there was little doubt that it had been carried out by the regime, particularly given their refusal to grant the UN access to the site immediately after the attack."

The two leaders also agreed that such an attack "demanded a firm response from the international community," according to the British government statement.

jm/lw (AP, Reuters)