Foreign Secretary William Hague has called on the United Nations to support moves led by the Arab League to bring a peaceful resolution to unrest in Syria.
Mr Hague made an impassioned plea at the UN Security Council in New York for action amid fears that Russia may block a draft resolution calling on the country's authoritarian leader Bashar Assad to step down and pave the way for a transfer of power.
Mr Hague said: "While we meet, the gravest of crimes are being committed in Syria. Responsibility for those crimes lies overwhelmingly at the door of the Syrian authorities ... We should unite behind the Arab League plan, and that is what I urge all members of the council to do, this week."
There was no doubt that the violence was worsening, he said.
"Six thousand Syrians have died, in appalling circumstances, and this includes 384 children. Between 30 and 100 people currently die every single day from the violence in Syria, they will be dying as we speak, thousands more are enduring torture, imprisonment and sexual violence, including the rape of children."
The risk of civil war was intensifying, and the threat to the stability of the region was growing, Mr Hague said. "With each day that passes, finding a way back from the brink will be harder and innocent lives will be needlessly and wrongfully lost, deaths which this council could help to avert by acting in a united manner."
The security council should remain seized of the situation in Syria, he said. "To fail to do so would be to undermine the credibility of this institution, betray the Syrian people, snub the Arab League, and fail in this council's responsibilities."
Western powers including Britain and France are pushing for the adoption of a resolution tabled by current security council member Morocco, which would give international backing to an Arab League timetable for the transition of power in Syria to a unity government, followed by free elections.
However Russia has been resisting a swift vote, saying it wanted to "study the recommendations and conclusions of the observer mission in detail" before moving to a substantive discussion in the council.
Deputy foreign minister Gennady Gatilov last week signalled that Moscow may wield its veto to block the draft resolution in its current form. In October, Russia and China blocked a Western-backed draft resolution condemning Assad's government for its crackdown on protesters.