The rising number of complaints by Muslims, which exceeds even the amount filed in the year after the 9/11 terrorist attacks, comes as tensions rise between Muslim Americans and those of other faiths.

Polls have shown that many Americans feel a growing wariness toward Muslims after the 9/11 attacks and after years of fighting in Iraq and Afghanistan. Mosques and Islamic community centers in the United States  most prominently one proposed near ground zero in Manhattan  have faced substantial opposition. And a Florida pastor received national attention this month for threatening to burn the Koran on Sept. 11.

“We can go back in history and find other times when there were hot emotional and political tensions over religion,” said Michael J. Zimmer, co-author of several books on employment discrimination and a law professor at Loyola University in Chicago. “Right now, there is a lot of heat as to the Muslims.”

Mohammad Kaleemuddin, a Pakistani immigrant who drove trucks for the American war effort in Iraq for three years, said that while he was working for a construction company in Houston, his supervisor and several co-workers called him “Osama,” “al Qaeda,” “Taliban,” and “terrorist.”

“It was very rough,” said Mr. Kaleemuddin, who was fired after protesting to management about the ethnic slurs. “It brought a bit of terror in my chest. I’d wonder, ‘Why are they doing this? I’ve always been nice to them.’ ”

After he filed a complaint, the E.E.O.C. sued the company he worked for, Pace Services. The company agreed last April to pay him $61,250 to settle the case.