Delegate Bob Marshall, one of the state legislature's most persistent abortion opponents, will announce his Republican candidacy for the U.S. Senate.

The 63-year-old Marshall, of Prince William County, has scheduled a state Capitol news conference Monday afternoon.

His announcement makes him the second Republican in the race. Former Governor Jim Gilmore is also running. The GOP nominee will be selected during the party's statewide convention in Richmond in June.

Former Governor Mark Warner is unopposed for the Democratic nomination to succeed retiring five-term Senator John Warner, a Republican. The Warners are not related.

Marshall has been a member of the House of Delegates since 1992.