SINGAPORE (AFP) - Oil prices fell in Asian trade Monday after United States President Barack Obama's announcement that he would seek approval from lawmakers for military action against Syria eased prospects of an imminent strike, analysts said.

New York's main contract, West Texas Intermediate for delivery in October, was down US$1.47 to US$106.18 (S$135.34) a barrel in mid-morning trade, while Brent North Sea crude for October fell US$1.15 to US$112.86.

US markets will be closed Monday for the Labor Day federal holiday.

"Investors are sitting back for now after President Obama's decision to take the decision on a Syrian intervention to US lawmakers," Mr Desmond Chua, market analyst at CMC Markets in Singapore, told AFP.

After the announcement on Saturday, Obama launched an intense lobbying effort to sway sceptical lawmakers as they weigh whether to support military action against Syria for its alleged chemical weapon use, an official said Sunday.

Although Syria is not a major oil producer, traders are nervous about a broader conflict in the crude-rich Middle East region, including neighbouring Iraq, which is becoming a major exporter.

Obama's surprise decision to hand the issue to the Congress effectively pushes military action back until at least September 9, when US lawmakers return from their summer recess.

It remains to be seen if a war-weary Congress will endorse Obama's push for action.

Secretary of State John Kerry said Sunday that Washington has proof the Syrian regime used sarin gas in a deadly August 21 strike on a Damascus suburb.

Hair and blood samples given to the US by emergency workers who rushed to the scene of the attack showed signs of the powerful sarin nerve gas, he said.

Mr Chua said all eyes will be on President Obama at a G20 summit in Russia later this week, where Syria is likely to top the agenda.

"There will be keen attention among investors on discussions about Syria at the G20 summit as well as the outcome of any direct meeting between President Obama and Russian President Putin," he said.