A museum is accused of firing an Afghan-American Muslim man on the basis of his national origin and religion shortly after the Sept. 11 attacks.

A manufacturer allegedly fired a naturalized U.S. citizen of Palestinian descent within days of Sept. 11 for no other reason than his national origin.

These cases are reflected in separate lawsuits filed by the Equal Employment Opportunity Commission based on Sept. 11 backlash, highlighting discrimination based on national origin.

Complaints of discrimination based on national origin have risen 20 percent over the last eight years, the EEOC said Tuesday.

The agency attributed the rise to hostility to Muslims and Middle Easterners after the Sept. 11 attacks, increasing numbers of immigrants in the labor force and other population changes.

"Most people think about race and gender discrimination — national origin discrimination doesn't come to mind, but it's having a greater impact on the workplace,'' EEOC spokesman David Grinberg said Tuesday as the agency announced its Web site's new user-friendly explanation of how discrimination law works. It can be found at http://www.eeoc.gov.

The Sept. 11 reaction has also caused problems for Sikhs, Asians and Arabs. Between Sept. 11, 2001, and November of this year, 688 charges have been filed by people of these national origins and others alleging Sept. 11 backlash discrimination — some relating to religion.

The EEOC filed a lawsuit on behalf of a Muslim employee of a car rental company who said she was fired for covering her head with a scarf during the holy month of Ramadan a couple of months after the Sept. 11 attacks. The company had not objected when she wore the scarf during Ramadan the previous two years.

The three lawsuits were all filed Sept. 30.

Of the roughly 84,000 total charges filed to the EEOC during the fiscal year that ended Sept. 30, about 11 percent, or 9,052, allege discrimination on the basis of national origin. That's up roughly 20 percent from 1994, when 7,414, or 8 percent, of total cases filed dealt with national origin bias, the EEOC said.

Commission officials said the 9,052 charges filed in the last fiscal year likely represents only the tip of the iceberg, that a lot of discrimination may be unreported because many fear retaliation or are not aware of the law.

To help educate employers about their responsibilities and employees about their rights, the commission has posted on the Internet a plain language explanation and a fact sheet.

Randy Johnson, vice president for labor policy at the U.S. Chamber of Commerce, welcomed the changes.

"EEO laws, as interpreted by the courts, have become extremely convoluted and difficult to understand,'' Johnson said. "We've always believed if the government's going to impose obligations on employers, it ought to spend some money on explaining what they are in plain English.''

The EEOC is a federal agency that enforces anti-discrimination laws in the workplace.