The visit is McCain's first to Iraq since he was named the presumptive presidential nominee for the Republican Party in February, CNN reported.

McCain was part of a U.S. congressional delegation including Sen. Lindsey Graham, R-S.C., and Democrat-turned-Independent Sen. Joseph Lieberman of Connecticut.

All three members of the Senate Armed Services Committee members are advocates of the "surge" that called for more U.S. soldiers in Iraq, CNN said.

McCain, meanwhile, responded to Democrat charges that he is spending taxpayers' money to advance his presidential aspirations by saying the trip to Iraq is justified by his seat on the Senate Armed Services Committee.

McCain's itinerary for the complete six-day journey includes meeting with leaders in Iraq, Israel, Jordan, France and England.