The American security firm Blackwater has ended its operations in the Iraqi capital Baghdad.
However the company will continue work in other parts of Iraq until September.
The Iraqi government banned Blackwater, now renamed, after its security guards killed up to 17 civilians in Nisoor Square, Baghdad, in 2007.
In January, the US government said it would not renew the company's task orders. Another US firm, Triple Canopy, takes over the contracts.
The Blackwater company began its work protecting US government personnel in Iraq following the invasion in 2003.
The shootings in Nisoor Square, in September 2007, led to a debate about the role the private security companies operating in Iraq.
An Iraqi investigation found that 17 civilians died, and were 20 wounded, when Blackwater guards opened fire while escorting an American diplomatic convoy. The company said its employees had come under attack by insurgents.
US prosecutors say 14 civilians were killed. Five former Blackwater guards pleaded not guilty to manslaughter and other charges in a US court in January.
Xe has defended its work in Iraq. The company's spokeswoman, Anne Tyrrell, said: "When the US government initially asked for our help to assist with an immediate need to protect Americans in Iraq, we answered the call and performed well.
"We are proud of our success - no-one under our protection has been killed or even seriously injured."
Guards from the Xe company will remain in Iraq until August protecting American diplomats in three cities south of Baghdad. And it will continue to provide helicopter escorts throughout Iraq until September.(EDITED FOR SAUCE: http://news.bbc.co.uk/2/hi/middle_east/8038549.stm)