Senior Syrian officials could be denied entrance to Britain for the Olympic Games, after reports emerged of atrocities against children.
Horrific video and images of dozens of dead children covered in blood came out of Syria yesterday - part of an attack which took at least 90 lives, including 32 young people.
Speaking on the Andrew Marr programme this morning, Nick Clegg said he could not speak for the International Olympic Committee (IOC) but that the government would not allow human rights abusers into the country.
"A principled presumption has now been introduced by us... if you've been shown to abuse human rights, you're not allowed in," he said.
Foreign Office minister Alistair Burt said: "It is clear that certain figures shouldn't be contemplating a visit to the United Kingdom."
The comment suggests general Mowaffak Joumaa, a friend of President Bashir Assad, may be denied entry, along with other senior officials.
The IOC has already stated that Syrian athletes will be able to compete in the games, but Mr Burt refused to rule out barring them when he did media appearances this morning.
Meanwhile, Syrian opposition groups started issuing hostile statements about UN observers, after it emerged local people notified them of the attacks, but they failed to stop them.
Observers later visited the town and reported use of "small arms, machine gun[s], artillery and tanks" but did not say who was responsible.
British foreign secretary William Hague called for a strong global response and an urgent session of the UN Security Council in the next few days. He has also called Syria's chargé d’affaires to the Foreign Office tomorrow.
France said it would make arrangements for a Friends of Syria meeting, which can function as a vehicle to unite Western and Arab nations while excluding Russia and China, who have prevented action against Syria at the UN.
"Those responsible for this massacre must be held to account for this appalling crime," said shadow foreign secretary Douglas Alexander.
"We fully support the government's call for an immediate meeting of the UN Security Council.
The attack was one of the bloodiest since the uprising against President Bashir began in March 2001.