Iraq says three mortar rockets have been fired at residential districts in Baghdad by what it described as agents of Iran.
The Iraqi news agency, quoting a security official, said one civilian was wounded and several houses damaged. He is reported to have said the crime will not go unpunished.
There has been a recent increase in tension between Iran and Iraq with each saying the other is letting opposition groups launch cross-border attacks from its territory.
There has been no immediate comment from Iran.
Dawn attack
The Iraqi security official did not give the exact location of the attack or any evidence that Iran was behind it.
He simply told the Iraqi news agency that agents of the Iranian regime fired three rockets at residential districts in Baghdad before dawn on Sunday. He said a fourth rocket did not explode and added that the authorities found equipment for firing them. Tension across borders The Iraq-based Iranian opposition group, the People's Mujahideen, has launched several successful rocket attacks against government targets in Iranian cities including the capital, Tehran. The most recent was at the end of last month. Iran has in the past retaliated by strikes against the group's bases in Iraq. But the Iraqi authorities believe that Iran also takes revenge by encouraging the Iraqi Shiite groups to fire similar mortar attacks inside Iraq. Both countries usually deny any involvement in such attacks. The activity of the opposition forces is an important stumbling block to improving relations between Iran and Iraq. The two neighbours fought a bloody war in the 1980s and have not signed a peace treaty since a ceasefire in 1988.