DALLAS, Aug. 20 (UPI) -- As the last U.S. combat troops leave Iraq, former President George W. Bush expressed thanks to the U.S. military for its service in Iraq.

Bush has rarely spoken about the war since leaving office, even as violence decreased and the United States prepared to withdraw fully by the end of next year, Politico reported.

"President Bush is always proud of our troops," Bush spokesman David Sherzer said in a statement to the Washington publication. "Like all Americans, he is deeply grateful for all they do to defend our country and help make the world a freer and more peaceful place."

In a posting on Twitter made as the last U.S. combat troops withdrew from Iraq to Kuwait, Sen. John McCain, R-Ariz., said Bush "deserves some credit for victory."

Bush and his supporters have contended a surge of U.S. troops he authorized in 2007 was the right move, insisting the additional troops helped lead to improved security conditions that made possible the withdrawal of combat troops.