Armed men have ambushed an Iranian embassy convoy in Baghdad, wounding three Iranians, including two diplomats, and an Iraqi, according to a diplomatic spokesman.

The convoy was on its way to a shrine in the northern neighbourhood of Kadhimiya when it came under fire, Manoucher Taslimi, an Iranian embassy spokesman, said on Friday.

The attack occurred the previous day as the convoy approached a bridge that links Kadhimiya with the predominantly Sunni area of Adhamiya, according to Taslimi.

He said those wounded, including an Iranian and an Iraqi administrative employee, were in stable condition.

Iran blamed the US for the ambush, saying Washington's threats against it encourage terrorist attacks against Iranian interests in Iraq.

"The suspicious behavior of US forces in security issues has brought increasing insecurity in Iraq," Mohammad Ali Hosseini, an Iranian foreign ministry spokesman, said in a statement, a copy of which was made available to the Associated Press news agency.

"Responsibility for providing security to diplomats as well as diplomatic and international bodies in Iraq rests with the occupiers."

Hosseini said threatening statements by US authorities against Iran were only encouraging fighters to carry out terror attacks.