Syria crisis: UN complains after inspectors fired on
The UN is to complain to the Syrian government and rebels after a convoy of chemical weapons inspectors came under sniper fire.
UN Secretary General Ban Ki Moon said he would ask the inspection team in Damascus to register "a strong complaint" so it never happened again.
The team is looking at five sites near Damascus where hundreds are reported to have been killed last week.
Russia has warned strongly against Western military action against Syria.
The tone of the White House is now much harsher towards the Syrian government - more certain that the deaths last week were caused by a chemical weapons attack and that it was carried out by President Bashar al-Assad's government.
A statement derided the idea of the inspectors being allowed in now, suggesting shelling had already destroyed the evidence.
Doubtless there will be similarly pointed words about the shooting at the inspectors as they attempted to begin an investigation.
President Obama was given a range of military options and spoke to the leaders of his key military allies, Britain and France.
Three US warships are in the region and many in Congress are calling for them to carry out a limited cruise missile strike.
But it would be surprising if President Obama took action without trying to obtain the maximum possible international backing, and that probably means giving the UN route more time.
Russian Foreign Minister Sergei Lavrov said any intervention in Syria without a UN mandate would be a "grave violation of international law".
The West, he told a news conference in Moscow, had not been able to come up with any proof of chemical weapons use while "saying at the same time that the red line has been crossed and there can be no delay".
He was responding to suggestions from some Western countries that military action against Syria could be taken without a UN mandate over the suspected use of chemical weapons by government forces.
The UN Security Council is divided, with Russia and China opposing military intervention.
UK Foreign Secretary William Hague told the BBC that action could be taken without UN approval if there was "great humanitarian need" in Syria.
His French counterpart Laurent Fabius suggested the UN Security Council could be bypassed "in certain circumstances".
Washington has recently bolstered its naval presence in the eastern Mediterranean, and military leaders from the US, UK and their allies are meeting in Jordan.
President Obama suggested last year that the use of chemical weapons by the Syrian government would be equivalent to crossing "a red line" which could trigger military action.Car attacked
Shortly after setting out from their central Damascus hotel, the UN inspectors were fired on by unidentified snipers.
The tyres and windscreen of the lead car in their convoy were hit multiple times, the UN said. The convoy, which was entering a buffer zone between government and rebel-controlled areas, was forced to turn back before resuming the drive to the western district of Muadhamiya.
Syrian state media blamed opposition "terrorists" for the attack, though the claim could not be verified. Rebels, in turn, have accused government forces.
Mr Ban, speaking in South Korea, condemned the shooting after a telephone briefing from his UN disarmament chief in Damascus, Angela Kane.
"I have instructed Angela Kane to register a strong complaint to the Syrian government and authorities of opposition forces so that this will never happen and the safety and security of the investigation teams will be secured from tomorrow," he said.
The UN Secretary General also gave more details of what the inspection team had done in Muadhamiya - the first of the five sites they have visited.
They went to two hospitals, interviewed witnesses, survivors and doctors, and collected some samples, he said.
In video posted on the internet, which the BBC has not been able to fully authenticate, one resident appears to tell an inspector of heavy raids on the district, with "over 600 canister strikes...12 tanks, 100 soldiers".
The US said there was little doubt that Syrian forces used chemical weapons in the attacks, which reportedly killed more than 300 people in rebel-held areas.
Syrian President Bashar al-Assad dismissed the accusation as "an insult to common sense" and warned the US against military intervention.
"If someone is dreaming of making Syria a puppet of the West, then this will not happen," he told the Russian newspaper Izvestiya.
Western officials were unimpressed with Syria's decision to allow in the UN experts.
Mr Hague said evidence could have been tampered with, degraded or destroyed in the five days since the attack.
A senior White House official, quoted by AP news agency, dismissed the visit as "too late to be credible".
However, a spokesman for the UN secretary general, Farhan Haq, expressed confidence that the inspections would produce results.
"We do expect that the evidence that the team is gathering will be useful to getting to the bottom of the events of 21 August," he told reporters.
Medecins Sans Frontieres (MSF) said on Saturday that three hospitals it supports in the Damascus area had treated about 3,600 patients with "neurotoxic symptoms" on Wednesday morning, of whom 355 had died.
While MSF said it could not "scientifically confirm" the use of chemical weapons, staff at the hospitals described a large number of patients arriving in the space of less than three hours with symptoms including convulsions, pinpoint pupils and breathing problems.
Syria's security forces are widely believed to possess large undeclared stockpiles of mustard gas and sarin nerve agent.
- 01:15: 21 August (10:15 GMT 20 Aug): Facebook pages of Syrian opposition report heavy fighting in rebel-held eastern districts of the Ghouta, the agricultural belt around Damascus
- 02:45: Opposition posts Facebook report of "chemical shelling" in Ein Tarma area of the Ghouta
- 02:47: Second opposition report says chemical weapons used in Zamalka area of the Ghouta
- Unverified video footage shows people being treated on pavements in the dark and in a makeshift hospital
- Reports say chemical weapons were used in Ghouta towns of Irbin, Jobar, Zamalka and Ein Tarma as well as in Muadhamiya to the west, but this is not confirmed
- Syrian government acknowledges military offensive in the Ghouta but denies chemical weapons use