Rep. Lane Evans, an Illinois Democrat who has battled Parkinson's disease for more than a decade, announced Tuesday that he will not seek re-election.

"This is a tough day for me," the 12-term lawmaker said in a statement, adding that he has "come to recognize that the time needed to address my health makes it difficult to wage a campaign and carry out my work as representative."

Evans, who was diagnosed with Parkinson's in 1995, has not been able to attend congressional meetings or cast votes since receiving medical attention on Feb. 14, according to his office. Evans, 54, was briefly hospitalized and has been home in Washington, D.C., since then.

"I will return soon and to the best of my ability complete the important work of this term," Evans said, closing with the Marine Corps motto, "Semper fi." Evans served in the Marine Corps from 1969-71.

Evans' 17th congressional district — which encompasses Moline, Rock Island and parts of Springfield — is certain to be competitive in November. In 2004, Democratic nominee John Kerry captured the district with 51 percent of the vote.

Illinois held its primary last week and local Democratic officials will decide on who would replace Evans on the November ballot. Evans ran unopposed in the primary and was to face Republican Andrea Zinga, a repeat challenger who captured 39 percent of the vote in 2004.

A potential replacement is Democratic state Sen. Mike Jacobs, who said he had not talked to Evans and his staff but had been approached by others about running.

"Like everyone in my district, I'm saddened by the news," Jacobs said in Springfield, Ill. "His brain works fine, but his mouth just couldn't give the words. ... We are losing a great friend to our district."

After his diagnosis, Evans didn't go public with his illness for three years, fearing that the revelation would stigmatize him. Evans has said that he first realized something was wrong when he attended a parade and could not wave his left hand.

Two years ago, Evans said his illness "doesn't prevent me from doing my job 365 days a year." He said he still ran twice a week and maintained a hectic congressional schedule.

Evans is the top Democrat on the House Veterans Affairs Committee and a leading member on the Armed Services Committee.