WASHINGTON (REUTERS) - Most Americans do not want the United States to intervene in Syria's civil war even if the government there uses chemical weapons, a Reuters/Ipsos poll showed, in a clear message to the White House as it considers how to respond to the worsening crisis.

Only 10 per cent of those surveyed in the online poll said the United States should become involved in the fighting.

Sixty-one percent opposed getting involved.

The figure favouring intervention rose to 27 per cent when respondents were asked what the United States should do if President Bashar al-Assad's forces used chemical weapons.

Forty-four per cent would be opposed.

"Particularly given Afghanistan and the 10th anniversary of Iraq, there is just not an appetite for intervention," said Ipsos pollster Julia Clark.

The rebellion against Mr Assad's government has resulted in 70,000 dead and created more than 1.2 million refugees since it erupted in 2011.

President Barack Obama has shied away from deep US involvement, although he declared last year that the use or deployment of chemical weapons by Mr Assad's government would cross a "red line."

Mr Obama said on Tuesday there was evidence those weapons had been used, but too much is still unknown for Washington to do more than provide the non-lethal aid it is already sending to the Syrian rebels.

He did not rule out action - military or otherwise - against Mr Assad's government. But he repeatedly stressed he would not allow himself to be pressured prematurely into deeper intervention in Syria's two-year-old civil war.

Many Americans are still oblivious to events in Syria. The poll found that about one-third, or 36 per cent, had neither heard nor read anything about the civil war there.

Only 8 per cent said they had heard or read a great deal and 19 per cent said they had heard or read a "fair amount." The online poll of 519 Americans aged 18 and over was conducted from April 26-May 1. The survey has a credibility interval of plus or minus 4.9 percentage points.