UK to present a resolution to the UNSC on Syria

The UK will present a resolution to the UN Security Council on Wednesday for "authorising necessary measures to protect civilians" in Syria against the use of chemical weapons.

The resolution will be put forward at a meeting of the five permanent members of the Security Council, British Prime Minister David Cameron said on Twitter.

Russia and China have previously vetoed resolutions critical of Syria and may block any text deemed to approve military action.

A statement from 10 Downing Street said Britain will seek a measure "authorising necessary measures to protect civilians" in Syria under Chapter 7 of the UN Charter.

Military force is one of the options that can be authorised under that chapter.

Earlier, Cameron spoke to US President Barack Obama on phone as the two countries considered military intervention in Syria.

Downing Street said Cameron heard the "latest on US thinking" on the issue, ahead of a National Security Council meeting and a House of Commons vote tomorrow.

Cameron has called the parliament back into an emergency session tomorrow for a debate on Syria and a vote that is expected to endorse possible military action.

"No decision has yet been taken. Any action we take or others take would have to be legal, would have to be proportionate," Cameron said.

"It would have to be specifically to deter and degrade the future use of chemical weapons, he said in an interview yesterday.

Cameron said the "question we need to ask is whether acting or not acting will make the use of chemical weapons more prevalent".

The Syrian government has blamed opposition fighters for an alleged chemical attack near Damascus on August 21, in which hundreds of people were reportedly killed.

The phone call between Obama and Cameron was the second since the alleged attack.

The UK government is expected to publish the House of Commons motion for debate today, along with details of intelligence linking the Syrian government to the attack.

The motion is expected to stress the need for "appropriate measures" in response to the use of chemical weapons by any country.