The 13 UN inspectors reportedly left their hotel in central Damascus shortly before dawn and have now arrived in Lebanon.

The team was tasked with investigating the alleged use of chemical weapons at three sites in Syria.

Rebels accuse the Syrian government of carrying out a toxic gas attack in eastern Damascus on August 21. The government has rejected the claims.

UN spokesman Martin Nesirky told a briefing in New York that UN Secretary General Ban Ki-moon was ready if necessary to report to the Security Council on the team's investigation this weekend.

Any UN findings will not identify culpability. The investigators have a mandate only to check whether chemical weapons were used.

'Wide range of military options'

This comes after US President Barack Obama on Friday said he was looking at a "wide range of options" for military intervention in Syria. He however stressed that none of them would involve putting "boots on the ground."

The US President said a long-term campaign was out of the question.

Obama was speaking after the US released an intelligence report on alleged chemical attacks in Damascus on August 21. That report, citing "a large body of independent sources," said US authorities were convinced that President Bashar al-Assad's forces were behind the attacks.

"Our high confidence assessment is the strongest position that the US Intelligence Community can take short of confirmation," the report said. According to the US data, 1,429 people were killed in the August 21 attacks. The report also specified that 426 of the dead were children

The Syrian government rejected the abridged US intelligence report.

"After days of exaggerations ... US Secretary of State John Kerry depends on old lies and fabricated reports published by the terrorists over a week ago," state news agency SANA quoted a foreign ministry source as saying.

Coalition of deux willing?

France was the only other permanent member of the UN Security Council to immediately state a readiness to intervene in Syria.

President Francois Hollande had told the Friday edition of newspaper "Le Monde" that he and Obama "agreed that the international community cannot tolerate the use of chemical weapons, that it should hold the Syrian regime accountable for it and send a strong message."

Kerry on Friday described France as "our oldest ally," as he listed a comparatively slim set of potential members for a future alliance in Syria - not including the UK. He was speaking a day after British parliamentarians rejected Prime Minister David Cameron's plan to authorize military intervention in Syria.

Bundeswehr unlikely to mobilize

German Foreign Minister Guido Westerwelle on Friday suggested that Berlin was unlikely to send troops or planes to Syria.

"No one has asked us to take part in such an action, nor are we considering it," Westerwelle said when asked about the possibility of military action in Syria.

However, Chancellor Angela Merkel's spokesman, Steffen Seibert, said a chemical weapons attack against civilians and children "is a transgression of international norms that must not occur without consequences."

Seibert did not specify what the consequences could be, but said that Merkel was in constant contact with other world leaders.

Germany critical of Moscow and Beijing

Russia, perhaps Syria's closest ally during the civil war, reiterated its support for Assad on Friday.

"These threats are unacceptable," foreign ministry spokesman Alexander Lukashevic said in Moscow when asked about Obama considering minor military action. Lukashevic said that military action without UN Security Council approval would violate international law, and that it ran the risk of causing more casualties.

The German chancellor on Saturday criticized the stance of Russia and China, which have vetoed three UN resolutions to put more pressure on Assad.

"It is very regrettable that Russia and China have refused for some time to come to a common position on the Syrian conflict. This considerably weakens the role of the United Nations," Angela Merkel told the regional daily Augsburger Allgemeine.

tj, msh/ccp (AFP, AP, dpa)