Gary Condit said he was "close" to Chandra Levy

Mr Condit received 37% of the vote, while the rest was split between four other candidates.

There had been speculation that Mr Condit would not stand again after attracting widespread criticism over his behaviour during the inquiry into Chandra Levy's disappearance last year.

The young woman has still not been found.

Damaging mistake

Mr Condit has denied any involvement in her disappearance and police have said they do not consider him a suspect.

Washington police sources have said Mr Condit admitted he had an affair with Miss Levy, although in media interviews he has refused to reveal the exact nature of their relationship.

"I have done my job as a congressman, I have conducted myself as a gentleman," he told reporters shortly after casting his own vote in the primary.

"The only difference is the intrigue of what's happened over the last summer."

Several high-profile Democrats said Mr Condit's refusal to admit he had an affair with Miss Levy when the hunt for the missing intern first began irrevocably damaged his status, and the congressman has been under pressure to resign.

California governor Gray Davis and the state's two senators distanced themselves from Mr Condit.

Once among the most popular Democrats in the House of Representatives, Mr Condit, a right-wing Democrat, also lost the backing of his local party.

Democratic fears

Mr Condit's district has been redrawn to bring in working-class areas which are believed to prefer a left-wing member of the party.

Mr Condit has become unpopular with voters

Mr Condit had worked hard in vain on the election trail, paying special attention to ethnic groups and conducting door to door visits.

As the Democrat's nominee, Mr Cardoza will now face whoever wins a four-candidate Republican field for the reconfigured district.

The Republicans currently have a 10-seat advantage.

Mr Condit was first elected in 1989 and has been re-elected by voters six times.

Mr Cardoza, a former aide to Mr Condit, was backed by several prominent Democrats, including California Democratic Party Chairman Art Torres.