Washington ? Public support for military action against Iraq, while still in the majority, is slipping amid increased concerns about consequences, says a new poll. Six in 10 fear Iraq would use chemical or biological weapons in response.

Just over half, 55 percent, support military action against Iraq to replace Saddam Hussein, according to the poll by the Pew Research Center for the People & the Press. That is down from 64 percent in mid-September.

And support for such action drops by half to 27 percent if the United States is not joined by allies in such an effort.

“In addition to concerns about whether it is a multilateral effort, the public has deep concerns about chemical or biological attacks on U.S. troops, casualties or the higher risk of domestic terrorism,” said Andrew Kohut, director of the Pew Research Center. He said the concerns about the increased risk of terrorism here are almost 20 points greater than in 1991, before the Gulf War.

The poll of 1,751 adults was taken Oct. 17-27 and has an error margin of plus or minus 2.5 percentage points.