The legally required audit has helped sharpen the Pentagon's systems and controls and has regularly helped the Department of Defence find misplaced inventory, which saves money.

The most likely source of funding would be the US Department of Defense Ukraine Security Assistance Initiative, designed to support the country as it fights Russia, the report says.

Pentagon spokesman John Kirby says there were no US casualties.

Pentagon security did not offer any explanation for how the chicken made its way into the compound, or whether it posed any particular threat.

Poor or inadequate surveillance footage often contributed to deadly targeting failures, the report says.

Aimal Ahmadi lost his three-year-old daughter Malika and nine other relatives in the Aug 29 strike, which came as the US military scrambled to complete its withdrawal from Afghanistan.

The new group which will succeed the US Navy's Unidentified Aerial Phenomena Task Force, will work to detect, identify and attribute objects, assess and mitigate any associated threats, the Pentagon says.

Pressed by journalists, President Joe Biden did not rule out the possibility.

Pentagon spokesman John Kirby says there were 'a number' of US and civilian casualties.

Footage has shown the Taliban with firearms and vehicles that Pentagon troops used or provided to the Afghan national security forces, as well as advanced UH-60 Black Hawk attack helicopters.

The FBI's commitment is part of a legal battle waged by relatives of Sept 11 victims against Saudi Arabia and other nations they believe were accomplices.

Afghan military officials had complained that they were not told in advance that US forces would leave in the early hours last Friday.