U.S. Democrat candidate Jon Tester has won the crucial Senate race in Montana, bringing the number of Democratic seats in the 100-member Senate to 50, U.S. media reported Wednesday.
Tester won the seat with a small margin, defeating incumbent Republican Senator Conrad Burns, who was first elected in 1988, NBC television reported.
With 99 percent of precincts reporting, Tester got 49 percent of the vote against 48 percent for Burns, the report said.
Democrats have taken five Senate seats from Republicans, just one seat short for a majority in the Senate, in which the party has been in the minority since 2002.
Control of the Senate now hangs on the race in Virginia, between Republican incumbent George Allen and his Democratic challenger James Webb, a former Navy secretary. Webb was leading Allen by fewer than 9,000 votes out of more than 2.3 million cast.
Democrats have already won 228 seats in the 435-member House, against 196 seats for Republicans, retaking control of the House for the first time in 12 years.
Meanwhile, Democrats took 20 of 36 gubernatorial races, bringing the number of Democratic governorships to 28.
Tuesday's elections to a large extent was a national referendum on President George W. Bush and the war in Iraq, exit polls showed.
Sixty percent of voters leaving the polls said they opposed the war in Iraq, and 40 percent said their vote was a vote against Bush, The New York Times reported.