Three Katyusha rockets fell inside the Iraqi capital's heavily fortified Green Zone which houses government buildings and foreign missions at midnight on Monday. The rockets were launched from Zafaraniyah district outside Baghdad. Two rockets landed near the U.S. embassy. So far, there were no reports about casualties and it's unknown as to who fired the rockets.

The turmoil closely follows the resumed anti-government unrest after a lull of several weeks. Six Iraqis including two police officers were killed and scores wounded in Baghdad and other cities on Monday during clashes with security forces.

Three protesters succumbed to their wounds at a Baghdad hospital after police fired live rounds in Tayaran Square, the sources said. Two protesters were shot by live bullets while a third was hit by a tear gas canister. A fourth demonstrator was shot dead by police in the Shiite holy city of Karbala.

Protesters threw petrol bombs and stones at police who responded with tear gas and stun grenades.

In the Iraqi oil city of Basra, two policemen were struck and killed by a civilian car during a protest. The driver was trying to avoid the scene of clashes between protesters and security forces when he drove into the two officers, they said.

Elsewhere in southern Iraq, hundreds of protesters burned tires and blocked main roads in several cities, including Nassiriya, Karbala and Amara. They say Prime Minister Adel Abdul Mahdi has not fulfilled promises including naming a new government acceptable to Iraqis.

The Baghdad police said their forces had reopened all roads that were closed by "violent gatherings." They said 14 officers were wounded near Tahrir square, including some with head wounds and broken bones.

Mass protests have gripped Iraq since October 1, with mostly young protesters demanding an overhaul of a political system they see as profoundly corrupt and as keeping most Iraqis in poverty. More than 450 people have been killed.

Numbers had dwindled but protests resumed as demonstrators sought to keep up momentum after attention turned to the threat of a U.S.-Iran conflict following Washington's killing of Tehran's top general in an airstrike inside Iraq.

The killing of Qasem Soleimani, to which Tehran responded with a ballistic missile attack on two Iraqi military bases housing U.S. troops, has highlighted the influence of some foreign powers in Iraq, especially Iran and the United States.

(With input from Reuters)