DENVER (AP) – Jefferson County state Rep. Jon Keyser has announced his Republican candidacy for the U.S. Senate, hoping to challenge Democratic Sen. Michael Bennet.

Keyser, an Air Force Academy graduate and veteran of Iraq and Afghanistan, announced his run Monday. He said he will resign from the state House on Jan. 25.

Keyser joins a crowded GOP field that includes state Sen. Tim Neville of Littleton, El Paso County Commissioner Darryl Glenn, former Aurora City Councilman Ryan Frazier, former Parker Mayor Greg Lopez, businessman Robert Blaha and Jefferson County Commissioner Donald Rosier.

Bennet is seeking a second term. In 2010, he narrowly edged Republican Ken Buck, who won an open U.S. House race in 2014.

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