The victims included US troops, members of the Iraqi national guard, and Iraqi civilians, CNN said.

Fifty-one people were wounded in the incident -- which occurred at noon local time, said the network quoting officials who declined further details.

The attack came came shortly after British Prime Minister Tony Blair arrived on a surprise visit to Iraq.

Earlier Tuesday, the US Air Force launched airstrikes on insurgents fighting American troops west of Baghdad Tuesday. a US military spokesman said.

"At approximately 2 a.m. this morning [6 p.m. ET Monday], a U.S. Air Force aircraft, in support of troops in contact, engaged an enemy fighting position with precision weapons," CNN quoted st Sgt. Steve Valley with the Combined Press Information Center as saying.