RICHMOND, Va. (AP) — Former GOP Gov. Jim Gilmore announced Monday that he will seek the U.S. Senate seat held by retiring Republican John Warner.

Gilmore's announcement sets up a campaign with another former governor, Democrat Mark R. Warner — a clash between two men with vastly different views about government and little affection for the other.

Gilmore, 58, made the announcement in a video e-mailed to 5,000 supporters and reporters. It was also posted on YouTube and other Web sites and announced in 70,000 letters mailed to backers Friday.

"I was governor of Virginia when our nation was struck on Sept. 11, and I helped Virginia deal with the aftermath of the attack on the Pentagon," Gilmore said in the nearly four-minute video.

Gilmore said in an interview that he will stress his military and national security background against Mark Warner, who did not serve in the military.