David Cameron said he has not ruled out stepping up action against the Syrian regime after growing evidence they were using chemical weapons, according to Reuters.
Cameron told NPR radio: "Certainly we haven't ruled out stepping up action in response to what seems to be happening on the ground.
"The evidence is growing; the lack of room for doubt is shrinking, and I think this is extremely serious."
The Prime Minister said he would raise the issue with US President Barack Obama at their meeting today.
More top news
Demonstrators jumped the barrier and lay down on the red carpet to draw attention to cuts to domestic abuse services.
Doctors in Australia have reattached 16-month-old Jaxon Taylor's head to his spine after he was 'internally decapitated' in a car accident.
Alan Titchmarsh becomes the new chancellor at the university where I and my daughter both studied, writes Alastair Stewart.