William Hague faces pressure to set out the UK's strategy on Syria to MPs after the United Nations failed to agree a resolution seeking an end to the mounting violence.
The Foreign Secretary urged Arab nations to push ahead with efforts to force a peaceful solution in the wake of a widely-condemned veto by Russia and China ended hopes of a UN-backed push.
But with the death toll mounting ever faster, Labour called on Hague to come to the Commons to "explain the government's position and the next steps to be taken".
He indicated yesterday that the UK would seriously consider severing diplomatic ties with Damascus if the Arab League followed Tunisia in expelling Syrian ambassadors.
But he insisted that military action like that taken in Libya was not being considered.
Diplomatic deadlock at the UN on Saturday came just hours after the bloodiest bombardment of the 11-month crackdown on pro-democracy protests - with up to 200 reported dead in the city of Homs.
Hague conceded that the country appeared to be slipping towards all-out civil war between anti-regime groups and the security forces controlled by President Bashar Assad.
Russia and China bore some responsibility for future deaths if the violence continued and escalated, he said, as their refusal to back an Arab-led plan would serve to embolden the regime
But the way forward was for the Arab League, with the backing of Western nations, to "intensify their own pressure on the Assad regime to stop the killing and allow a peaceful transition".
He said the UK would hold talks with Arab League member states ahead of a meeting of their foreign ministers this week. Russia's foreign minister is due in Damascus tomorrow.
Asked if Britain would join a diplomatic boycott by the Arab League, Mr Hague said: "Any decision by them to do that would weigh very heavily with us."
Shadow foreign secretary Douglas Alexander said the UN stalemate was "a stain on the conscience of the world" - and called for tougher travel and asset bans and sanctions.
"It is deeply regrettable that Russia and China chose to veto what would otherwise have been an international consensus around the Arab League peace plan.
"I will be urging William Hague to come to the House of Commons to explain the Government's position and the next steps to be taken.
"It is already clear that the Assad regime has no future.
"The tragedy is that notwithstanding that, the slaughter continues and so every diplomatic effort must be made to stop the continued bloodshed."
He told Sky News: "We need to put our shoulders to the wheel in support of the efforts that are being made by the Arab League to deepen the isolation and to intensify the pressure. It is already having an effect but we need to accelerate the timetable."
Suggested For You
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements. Learn more