BAGHDAD - Two Katyusha rockets on Wednesday landed near the US embassy in the heavily fortified Green Zone in central Baghdad, an Interior Ministry official said.

The attack took place around midnight when the two rockets landed near the US embassy in the Green Zone which also houses some of the main Iraqi government offices, the official told Xinhua on condition of anonymity.

There were no immediate reports about casualties, the source said.

The heavily fortified Green Zone has been frequently targeted by insurgents' mortar and rocket attacks. The roughly 10 square km zone is located on the west bank of the Tigris River, which bisects the Iraqi capital.

The attack came hours after Qais al-Khazali, leader of the Iraqi Iran-backed Shiite militia Asa'ib Ahl al-Haq, said the Iranian initial response to the killing of the Iranian military leader is done and it is time for Iraq to respond to the US airstrike.

Al-Khazali's threat came after Iran fired ballistic missiles earlier in the day on military bases housing US troops in Iraq's western province of Anbar and near the city of Erbil, capital of the semi-autonomous region of Kurdistan.

Last week, a US drone attacked a convoy at Baghdad International Airport, killing Qassem Soleimani, commander of the Quds Force of Iran's Islamic Revolution Guards Corps, and Abu Mahdi al-Muhandis, deputy chief of Iraq's paramilitary Hashd Shaabi forces.

More than 5,000 US troops have been deployed in Iraq to support the Iraqi forces in the battles against Islamic State militants.