BAGHDAD - Iraqi supporters of pro-Iran factions attacked the US embassy in Baghdad on Tuesday, breaching its outer wall and chanting "Death to America!" in anger over weekend air strikes that killed two dozen fighters.

It was the first time in years protesters have been able to reach the US embassy, which is sheltered behind a series of checkpoints in the high-security Green Zone.

A stream of men in military fatigues, as well as some women, marched through those checkpoints to the embassy walls with no apparent reaction from Iraqi security forces.

US President Donald Trump in a Twitter message accused Iran of "orchestrating" the attack and said it "will be held fully responsible", but he also said he expected Iraq "to use its forces to protect the embassy".

The demonstrators waved flags in support of the Hashed al-Shaabi, a mostly Shiite network of Iraqi armed groups that has received training and weapons from powerful neighbour Iran.

They threw rocks and wrenched security cameras off the walls, ignoring calls over megaphones to leave the embassy compound.

In response, US guards fired an initial volley of bullets, then switched to tear gas and flash bang stun grenades to disperse the crowd.

The Hashed said at least 62 people were wounded.(FA)