Residents were seen stocking up with fuel for generators in case utilities are knocked out by a strike.
And as the inspectors crossed into Lebanon, they were followed by families desperate to flee.
Abu Malek, a 31 year old factory worker from near Damascus, said people at home were terrified.
“Those who can, leave. But many people can’t,” he told AFP after he crossed into Lebanon.
US Secretary of State John Kerry cited “multiple streams of intelligence” indicating that the Syrian government had carried out the chemical attack and that Assad himself is the “ultimate decision maker”.
Kerry said failure to act would not only erode the nearly century old norm against the use of chemical weapons, but would embolden Syrian allies Iran and Hezbollah.
Putin demanded proof.
“Common sense speaks for itself,” he told journalists in Vladivostok when asked about claims the Syrian army used chemical weapons.
They are “on the offensive and have surrounded the opposition in several regions. In these conditions, to give a trump card to those who are calling for a military intervention is utter nonsense.”
The Americans “say that they have proof, well, let them show it to the United Nations inspectors and the Security Council If they don’t show it, that means there is none.”
Russia and Iran, and even some US allies, have warned against any intervention, saying it risks sparking a wider conflict.
The United States, faced with an impasse at the Security Council and the British parliament’s shock vote Thursday, has been forced to look elsewhere for international partners.
While Germany and Canada ruled out joining any strikes, French President Francois Hollande whose country stridently opposed the US led war on Iraq said a British parliamentary vote rejecting participation would not affect his government’s stance.
Hollande said 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.”
Turkey, Syria’s neighbour, went further still. It demanded not just surgical strikes to send a message about chemical weapons but a sustained campaign to topple the regime.
Gruesome pictures of some of the reported victims of the attacks, including children, have shocked the world and piled on the pressure for a response that could draw a reluctant West into the vicious Syrian civil war.
Five US destroyers carrying hundreds of cruise missiles among them are believed to be in the eastern Mediterranean readying launches against Syrian munitions depots and command and control hubs.
US forces are also stationed at air bases in Turkey, and long-range bombers could eventually be sent from bases in North America.
France has warplanes stationed in Abu Dhabi and Djibouti, and naval assets in the Mediterranean.
More than 100,000 people have died since the Syrian conflict erupted in March 2011, and two million have become refugees, half of them children, according to the United Nations.