A rare daytime rocket attack hit Baghdad's Green Zone on Sunday, security sources said, as Iranian Foreign Minister Mohammad Javad Zarif met top Iraqi officials.

At least two rockets hit outside the US embassy in the high-security zone, the sources told AFP.

Diplomats based in the neighborhood said they could hear sirens blaring for around an hour after the attack.

The embassy's C-RAM rocket defense system was not triggered, possibly because the missiles' trajectory meant they would not strike within the compound.

The heavily fortified Green Zone has come under repeated rocket attacks in recent months. In late January, three out of five rockets that were fired directly hit the US embassy. At least one person was wounded.

The previous attacks usually occurred under cover of darkness, but this time, the attack took place in the searing afternoon heat as Iran's top diplomat held back-to-back meetings with senior Iraqi officials nearby, according to AFP.

Zarif first met his Iraqi counterpart Fuad Hussein early on Sunday, then Prime Minister Mustafa al-Kadhemi, President Barham Saleh, Parliament Speaker Mohammed Al-Halbussi and the head of Iraq's Supreme Judicial Council, Faeq Zeidan.

Zarif is also set to travel north to the Kurdish regional capital of Arbil to meet with officials there.

Iran has major military and political sway in Baghdad and is the second-largest exporter of consumer goods to Iraq.

But its influence irks both Saudi Arabia and the United States, which is urging Iraq to develop its diplomatic and economic ties to its Gulf neighbors.

A 2018 report said that Iran had transferred short-range ballistic missiles to its Shiite allies inside Iraq.

Iran rejected the report, claiming it aimed to harm Iran’s ties with its neighbors. Iraq’s Foreign Ministry said the article was “without evidence”, though it stopped short of denying its contents.