A SHI’ITE militant group that Washington alleges is sponsored by neighbouring Iran has claimed responsibility for this week’s rocket attack that killed five American soldiers in Iraq.

Ketaib Hezbollah said in a statement posted on its website on Friday that it was behind Monday’s bombing in the Baladiyat district in eastern Baghdad.

“The occupiers are still staining our soil,” the Arabic-language statement said, referring to American troops who have been stationed in Iraq since the 2003 US-led invasion and are readying to finish a pullout at the end of this year.

“We killed and wounded tens of their (US) soldiers with this attack,” the statement said.

A brief statement by the US military in Iraq said after the attack that “five US service members were killed Monday in central Iraq”, without giving other details.

Ketaib Hezbollah added it had several rockets “ready to be used at any time to target enemy bases, especially its embassy”, referring to the US embassy in Baghdad, the largest in the world and located inside the heavily fortified Green Zone that houses government ministries and many other embassies.

Nearly a year ago, the then top US military commander in Baghdad said Ketaib Hezbollah had received specialist training in Iran to help mount an attack on American military bases in Iraq.

Ray Odierno, who has recently been nominated by US President Barack Obama as his Army Chief of Staff, said in July last year that the Shi’ite insurgents had returned to Iraq after training in Iran, but it was not clear if the Iranian government was involved.

Washington accuses Iran of backing several Shi’ite insurgent groups in Iraq, which Tehran denies.

The number of US soldiers killed in Monday’s attack was the largest in a single day in more than two years.

Most US troops pulled out of Iraq after the American military formally ended combat operations at the end of August last year.

The remaining 45,000 US forces are primarily charged with training and equipping their Iraqi counterparts, although they still take part in joint counter-terror operations.

Their bases still come under frequent rocket attack by insurgents.

CIA chief Leon Panetta said on Thursday the United States should seriously consider any Iraqi request for US troops to stay beyond the year-end departure deadline.