The embassy said on Thursday a new visa scheme would allow 5,000 Iraqis in each year during a five-year period starting last month.

'With the launch of this special immigrant programme, we take a significant step toward ... providing safe haven to those brave Iraqi citizens who risked their lives in order to serve the United States,' Ambassador Ryan Crocker said in a statement.

The U.S. government and military has employed thousands of Iraqis since the 2003 invasion, and many have been killed or faced the threat of death from insurgents who view them as collaborators.

The U.S. government has been criticised for not doing enough to protect them.

Richard Albright, the U.S. embassy's senior coordinator for refugee issues, said Iraqis who worked for the United States longer than three months since March 20, 2003, may be eligible.

'Applicants must show they ... have experienced an ongoing serious threat as a result of that employment,' Albright said. He added: 'the recipients receive permanent residence in the United States; they can stay for the rest of their lives.'

The U.S. Department of Homeland Security last year accepted thousands of refugees under a resettlement programme after President George W. Bush's administration came under fire from Congress for taking only 466 Iraqi refugees since the war began.

An existing visa scheme for translators allows 500 Iraqis into the United States each year, so this effectively increases those admissions ten-fold and widens its scope, Albright said.

Britain started accepting Iraqi translators as refugees last November, after militants killed some of its interpreters.

Like other refugees to the United States, the immigrants can apply for refugee status for their families, including spouses, siblings, children, parents and grandchildren, Albright said. They also get help with accommodation, transport and healthcare.

(Reporting by Tim Cocks, editing by Mary Gabriel)