Since October, US diplomats and troops across Iraq have been targeted by around three dozen missile attacks which Washington has blamed on pro-Iranian armed factions.

In the first move of its kind, elite Iraqi troops in late June arrested more than a dozen Tehran-backed fighters who were allegedly planning a new attack on Baghdad's Green Zone, home to the US and other foreign embassies.

Iraqi government officials said the raid would serve as a "message" to deter future attacks, but early on Sunday, militants made another attempt.

One rocket fired at the Green Zone landed near a home, wounding a child, according to the Iraqi military.

"At the same time, our forces were able to thwart another attack and seize a Katyusha rocket and launcher that were targeting the Taji base north of Baghdad," where US-led coalition troops are based, it added.

The attempts came just hours after the US embassy tested a new rocket defence system known as a C-RAM, according to a senior Iraqi security source.

The C-RAM, set up earlier this year at the embassy, scans for incoming projectiles and explodes them in the air by targeting them with several thousand bullets per minute.

There was no immediate comment from the embassy on whether the system was used against the rocket overnight.