Robert Gates was said to share concerns about Blackwater
US Defence Secretary Robert Gates is to review allegations of misconduct in Afghanistan by the security company formerly known as Blackwater.
The review comes a day after a leading Democrat said the Pentagon should consider barring it from applying for a contract to train Afghan police.
The Pentagon said it could not bar the company from applying for the billion-dollar police training contract.
A spokesman for company, now called Xe, said it welcomed the review.
A spokesman for the company, Mark Corallo, said Xe has an excellent record of training security personnel in Afghanistan.
However, in a letter to Mr Gates at the end of February, Senate Armed Services Committee chairman Carl Levin cited allegations of misconduct against the firm made before the committee.
He said there was evidence of misconduct in a previous subcontract awarded to a Blackwater affiliate to conduct weapons training for the Afghan National Army.
Pentagon spokesman Geoff Morrell said of Mr Gates' response: "He is looking into it and he takes it seriously. He shares [Mr Levin's] concerns."
But he said it was not possible to bar the company without following strict regulations.
"You can't willy-nilly choose not to do business with a company," he said.
"There are strict criteria for pursuing debarment. They are afforded due process. They are afforded legal standards."
Mr Morrell also said that Blackwater has the necessary technical expertise.
"And they have a willingness to work in places that very few companies are willing to work. So they provide a much-needed service and the ability to do it well."
The Blackwater company began its work protecting US government personnel in Iraq following the invasion in 2003.
Anti-American sentiment in Iraq was stoked in December after a US judge threw out manslaughter charges against five Blackwater guards over the 2007 killing of 17 Iraqis in Baghdad.
The activities of foreign security firms in Iraq have been curbed since then.
About a month ago, Iraq ordered 250 former and current staff of Blackwater to leave within a week.
In January 2010, Xe finalised the settlement - for an undisclosed amount - of a number of lawsuits over the killings of Iraqi civilians.
The civil suits accused Blackwater's founder, Erik Prince, of cultivating a climate of recklessness.
The lawsuits sought compensation for deaths and injuries incurred in incidents including the 2007 killings.