They include Duncan Hunter, a Republican and Marine Corps reservist who is also the son of the incumbent, the San Diego Union-Tribune reported. Duncan Hunter Sr. is one of the most conservative members of Congress, best known as a hawk on illegal immigration and for his long-shot campaign for the Republican presidential nomination.

The other veteran candidates for Hunter's seat are Democrat Mike Lumpkin, a retired Navy SEAL commander who was in charge of the Joint Special Operations Task Force in Iraq, and Republican Rick Powell, a retired Army colonel who also served in Vietnam and was a supervisory special agent for U.S. Customs.

At least 32 Iraq War veterans are believed to be running for Congress -- 15 Democrats and 17 Republicans.

Ken Spain, a spokesman for the Republican Congressional Campaign Committee, said he believes Hunter's is the only district in which three vets are running.