Foreign Secretary William Hague, said: "We are increasing the pressure on the Assad regime and getting the message across that the international community is appalled by the murder of so many innocent people.

"So as part of that pressure today we have again called the Syrian charge in London here to the foreign office.

"He has been given seven days to leave the country. Other Syrian diplomats, two other diplomats, will be expelled at the same time.

"Our allies and partners around the world will be taking similar action.

"Of course we will seek other ways to increase the pressure - we are discussing in the EU a further tightening of sanctions."