U.N. chemical weapons experts investigating an alleged poison gas attack near Damascus left their hotel again Wednesday hoping to carry out their second field trip, which was delayed Tuesday for security reasons.
The team of about 20 inspectors left their hotel in the Syrian capital in a convoy of cars to visit the eastern Ghouta suburbs, where the Obama administration says President Bashar Assad's forces unleashed a chemical weapons attack on Aug. 21 that killed hundreds of people.
Local opposition activists told CBS News that the convoy had reached the town of Mleiha, in the sprawling Ghouta area, and videos posted online by the activists showed the U.N. inspectors interviewing patients at clinics in Mleiha and the nearby town of Zamalka.
On Tuesday, Vice President Joe Biden made it clear that regardless of what the U.N. inspectors find, the White House is now convinced the attack was carried out by Assad's forces.
The American government's assessment is based on the circumstantial evidence from videos posted on the internet, and, as CBS News correspondent David Martin reported Tuesday, intelligence -- much of it still classified -- ranging from intercepted Syrian communications to tests of tissue samples taken from victims.
Another key piece of circumstantial evidence which has been cited by both officials and analysts for days is the simple fact that the regime is the only entity in Syria known to have chemical weapons and the means to disperse them.
Based on that evidence, the U.S. has moved four missile destroyers into the eastern Mediterranean, close to Syria's west coast and reportedly joined by a British submarine, "ready" to launch a strike if and when it is ordered by President Obama, according to Defense Secretary Chuck Hagel.
Speaking Wednesday at The Hague, U.N. Secretary-General Ban Ki-moon sought to calm the situation, calling for the international community to give his inspection team in Syria time to "do its job."
"It is essential to establish the facts. A U.N. investigation team is now on the ground to do just that. Just days after the attack, they have collected valuable samples and interviewed victims and witnesses. The team needs time to do its job," he said.
He urged the United Nations Security Council not to be "missing in action" as the Syria crisis deepens. "Give peace a chance. Give diplomacy a chance. Stop acting and start talking," he said.
The U.N.'s envoy to Syria, Lakhdar Brahimi, said later Wednesday in Geneva that while "it does seem like some kind of substance was used" that killed hundreds of people, "international law says that any U.S.-led military action must be taken after" agreement in the 15-nation Security Council.
He added that President Obama's administration was "not known to be trigger-happy."
Russia and China have used their position as permanent members of the Security Council to block any harsher action against the Assad regime thus far, and those nations have both also urged the U.S. and its allies to refrain from military action. Russia, a long-time ally to the Assad regime, insists the evidence showing government culpability in the alleged chemical attack is inconclusive.
British Prime Minister David Cameron said Wednesday that the U.K. had drafted a resolution condemning Assad's government for the chemical attack, which he said would be circulated later in the day at a meeting of all five permanent Security Council member states. The U.S., Britain, Russia, China and France are the permanent members; the so-called P5 nations. Each one holds the power to veto any action taken by the Council.
Syria's foreign minister renewed Tuesday the regime's vehement denial of any involvement in a chemical attack, demanding that the U.S. "produce the evidence" of government culpability.
On Monday, the U.N. team collected samples and interviewed witnesses in a Damascus suburb. Their convoy was hit by snipers en route, but the experts were not hurt. They abandoned plans for a second site visit Tuesday due to unspecified security concerns.
In his news conference Tuesday, Syrian Foreign Minister Walid Muallem said the delay was a result of the rebel groups failing to "agree among themselves" to guarantee the U.N. team's security. Muallem sought to counter repeated accusations from Washington and its allies that the Syrian regime was delaying the inspectors' work. He insisted the government was "implementing its commitments" with the team.
The U.N. has said the team might stay in Syria longer than the initially scheduled two weeks. The current mandate expires on Sunday.