Cameron, Obama threaten 'serious response' if chemical weapons use in Syria confirmed

The United Kingdom and the United States have threatened a serious response if it emerges Syria used chemical weapons last week.

Prime Minister David Cameron and President Barack Obama were gravely concerned by 'increasing signs that this was a significant chemical weapons attack carried out by the Syrian regime'.

The two leaders had spoken over the phone for 40 minutes on Saturday, the BBC reports.

According to the report, the Syrian regime and opposition have accused each other over the attacks.

Cameron and Obama had 'reiterated that significant use of chemical weapons would lead to a serious response from the international community and both have tasked officials to examine all the options, the report said.

A White House official also said that the president has directed the intelligence community to gather facts and evidence to determine what occurred in Syria.