10.56pm BST

We're going to wrap up our live blog coverage for the day. Here's a summary of where things stand:

• US secretary of state John Kerry delivered a strongly worded, to some ears bellicose, speech in which he said a large-scale, indiscriminate chemical weapons attack occurred last week in Syria and there's little doubt it was perpetrated by the Assad regime. Kerry described his own emotional reaction to images from the aftermath of the attack, which he called a "cowardly crime" and "morally obscene."

• Kerry said "there must be accountability" for the attack, which he said violated international, historically established norms. The US will respond to the attack, he said. Kerry said he and other Obama administration officials are in talks with foreign allies and members of Congress. Quizzed on whether the US means to undertake a military response, White House spokesman Jay Carney hinted at a course of action more serious than arming the opposition.

• The attack occurred on 21 August in the eastern suburbs of Damascus. Doctors Without Borders estimates that 355 died and thousands were injured. Other groups have placed the number killed much higher.

• Russian president Vladimir Putin told UK prime minister David Cameron that Moscow did not have evidence of whether a chemical weapons attack had taken place or who was responsible. In his speech, John Kerry described such denial as morally suspect. Evidence of chemical weapons use "is undeniable," Kerry said.

• The White House questioned a mission undertaken Monday by UN inspectors to establish that a chemical attack had taken place. Washington said the evidence is clear: a chemical attack has happened. A convoy of UN inspectors in Damascus was fired on today as it traveled to the attack site. The inspectors were able to reach the site and collect samples and interview witnesses. The UN secretary general said the mission could succeed despite five days lapsing since the attack.

• UN inspectors only were able to stay at the attack site for an hour and a half and were unable to visit six sites where "chemical rockets" fell, a doctor who met with the inspectors told the Guardian. The doctor said he saw bullet holes in at least one UN vehicle.

• An unprecedented roster of senior officials among the Western powers and the United Nations began to speak of urgent action in Syria. "And every hour counts. We cannot afford any more delays," the UN secretary general said. "All the options are open," France's foreign minister said. "We have called for a strong response," the British foreign secretary said. "There must be accountability," Kerry said.