Clark defends McCain comments

(CNN) - Former NATO supreme commander Wesley Clark said Monday he stands by his criticism of Sen. John McCain despite a wave of criticism from the Republican presidential candidate's allies and Democratic contender Barack Obama's campaign.

"As an American and former military officer, I will not back down if I believe someone doesn't have sound judgment when it comes to our nation's most critical issues," Clark, who sought the Democratic presidential nomination in 2004, said in a written statement Monday evening.

McCain's supporters have complained about Clark's Sunday comments on CBS' "Face the Nation," when Clark said McCain's experience as a Navy pilot and prisoner of war did not necessarily qualify him to serve as commander-in-chief.