COLUMBUS, Ohio (AP) -- U.S. Sen. George Voinovich of Ohio will not seek re-election in 2010.

Voinovich said in a statement Monday that the challenges facing the state and country will require him to devote all of his energy to serving out his current term and that campaigning and fundraising would take time away from his work as a senator.

Voinovich also said he wants to spend more time with his wife, children and grandchildren.

The decision sets in motion a jockeying among big names in both parties to replace Ohio's senior senator. It also brings to four the number of GOP Senate seats that won't have an incumbent in 2010.

Former U.S. Rep. Rob Portman of Cincinnati is figured to be a strong contender among Republicans to run for the Ohio Senate seat.

Lt. Gov. Lee Fisher and U.S. Reps. Tim Ryan and Zack Space are potential Democratic candidates.

(Copyright 2009 by The Associated Press.  All Rights Reserved.)