CHICAGO (AP) - To loud cheers and a standing ovation from some 150 gay rights supporters, Gov. Rod Blagojevich on Friday signed a new law protecting gays and lesbians from discrimination.

Flanked by more than two dozen lawmakers and community activists, many of whom said they worked for decades to convince lawmakers to pass the measure, Blagojevich described the new law as a moral imperative.

"What we're doing today is older than scripture: Love thy neighbor," Blagojevich told the audience, many of whom held up small, rainbow-printed gay-pride flags. "It's what Jesus said when he gave his sermon on the mount: 'Do unto others what you would have others do unto you.'"

Opponents have argued that the new law is the first step toward legalization of gay marriage and would infringe on the rights of churches and civic groups to oppose homosexuality on moral grounds.

The law adds "sexual orientation" to the existing state law that protects people from bias based on race, religion or other traits. It allows people to file complaints with the Illinois Department of Human Rights if they believe they were denied a job, housing, public accommodation or credit because of their sexual orientation.

Illinois is the 15th state to bar discrimination based on sexual orientation. Local gay rights ordinances across Illinois already protected nearly half of the state's population from discrimination, according to state Sen. Carol Ronen, D-Chicago, sponsor of the bill.