DAKOTA DUNES, S.D. (AP) - Former Republican South Dakota Gov. Mike Rounds is forming a committee to explore a run for the U.S. Senate seat held by Democrat Tim Johnson.

That seat is up for election in November 2014. Rounds says if he does decide to run, he won't make an announcement until after this year's November elections.

Rounds served two terms as governor, from 2003 to 2009. He has talked openly about a possible Senate run since early this year. He says he's particularly worried about the country's debt and health care reform.

His decision to form an exploratory committee was first reported by KCCR radio in Pierre.

Johnson has represented South Dakota in Congress since 1986. He has not yet announced whether he will seek a fourth term.