UN chemical weapons experts investigating an apparent gas attack that killed hundreds of civilians in rebel-held suburbs of Damascus made a second trip across the front line to take samples. Secretary-General Ban Ki-moon pleaded for them to be given the time they need to complete their mission.
But the US, European and West Asian allies have already pinned the blame on Assad and, even without full UN authorisation, US-led air or missile strikes on Syria look all but certain, tho-ugh the timing is far from clear.
That has set Western leaders on a collision course with Mos-cow, Assad's main arms supplier, as well as with China, which also has a veto in the Security Council and disapproves of what it sees as a push for Iraq-style regime change despite US denials that President Barack Obama aims to overthrow Assad.
Uncertainty over how the escalation of the conflict at the heart of the oil-exporting West Asia will affect trade, and the world economy sent oil prices, and gold, to their highest levels in months while stocks fell.
PM David Cameron said Britain will propose a resolution on Wednesday at the Security Council in New York, seeking authority to take necessary measures to protect Syrian civi-lians. Sure of a veto, it seemed part of diplomatic strategy to isolate Moscow and rally a coalition behind Washington. We've always said we want the UN Security Council to live up to its responsibilities on Syria, he said.
Germany, Europe's economic superpower, urged Russia to back the resolution. But foreign minister Sergei Lavrov had said earlier that any attack will be folly.
UN chief Ban pleaded for unity in the Security Council after more than two years of paralysis during which Syria's civil war has split West Asia on sectarian lines and fuelled rival camps in the world body along divisions that echo the Cold War.
Syria is the biggest challenge of war and peace in the world today, he said in a speech at The Hague. The body entrusted with maintaining international peace and security cannot be missing in action. The Council must at last find the unity to act. It must use its authority for peace.
Ban's special envoy for Syria, Algerian diplomat Lakhdar Brahimi, said international law is clear in requiring Council authorisation for military action. But Western leaders have made it clear they are ready to do without it, citing precedents for foreign intervention to protect civilians.
No strikes are likely before Obama has an intelligence report on the gas attack. Its conclusions, however, are scarcely in doubt.