US President Barack Obama has ordered a probe into attempts to quash an investigation into the mass execution of Taliban prisoners in Afghanistan.
The New York Times had reported that top officials from the previous administration of president George W Bush discouraged separate probes by the Federal Bureau of Investigation, the State Department and the Pentagon.
They wanted to hush up the killing of up to 2,000 prisoners in 2001 because it was carried out by the forces of General Abdul Rashid Dostam, an Afghan warlord then on the Central Intelligence Agency's (CIA) payroll, it said.
Mr Obama told CNN television that he has asked his national security team to collect the facts, after which a decision will be made on how to approach the matter.
"I think that, you know, there are responsibilities that all nations have, even in war, Mr Obama told CNN. The network planned to air the full interview on Tuesday.
A powerful commander in control of a section of northern Afghanistan, General Dostam first allied with the Soviets during their invasion of the country in the 1980s.
Later he sided with the Americans and received military and CIA support after the United States invaded Afghanistan in the wake of the September 11, 2001 attacks.
His militia worked closely with US Special Forces and was part of the Northern Alliance, which helped the United States topple the Taliban.
The killings took place in late November 2001, shortly after the invasion that ousted Kabul's Taliban government.
Taliban prisoners captured by General Dostam's forces after a major battle in northeastern Kunduz province were allegedly packed into shipping containers and left to suffocate, or were shot through the container walls before being buried in mass graves.
Estimates of the number of people killed have ranged from several hundred to several thousand.