The UN has delivered a withering verdict on the US's human rights record, raising concerns on a series of issues including torture, drone strikes, the failure to close Guantánamo Bay and the NSA's bulk collection of personal data.

The report was delivered by the UN's human rights committee in an assessment of how the US is complying with the International Covenant on Civil and Political Rights [ICCPR], which has been in force since the mid 1970s.

The committee, which is chaired by the British law professor Sir Nigel Rodley, catalogued a string of human rights concerns, notably on the mass surveillance exposed by the whistleblower Edward Snowden.

It said the collection of the contents of communications from US-based companies under the Prism program had an adverse impact on the right to privacy. It added that the legal oversight of such programs had largely been kept secret and failed to protect the rights of those affected.

The UN committee urged the US to overhaul its surveillance activities to ensure they complied with US law and conformed to US obligations under the ICCPR.

The comments come as the Obama administration sets out how it proposes to end the mass collection of Americans' phonecall data and make the searching of records held by telephone companies subject to a court order.

In its 11-page report, the committee also criticised the US for failing to prosecute senior members of its armed forces and private contractors involved in torture and targeted killings.

It noted that only a "meagre number" of criminal charges had been brought against low-level operatives. It also expressed concern that all investigations into enforced disappearances and torture conducted under the CIA's rendition programme were closed in 2012, and that the details of the programme remained secret, creating barriers to accountability and redress for victims.

The US is urged to "ensure that all cases of unlawful killing, torture or other ill-treatment, unlawful detention, or enforced disappearance are effectively, independently and impartially investigated, that perpetrators, including, in particular, persons in command positions, are prosecuted and sanctioned".

The committee was also scathing about Washington's legal justification for targeted killings using drones. The US claims such strikes, which have killed dozens of insurgents and civilians, are an act of self-defence as part of armed conflicts with al-Qaida and the Taliban. The committee criticised such justifications as too broad, and said it was unclear what precautionary measures were taken to avoid civilian deaths.

It urged the US to review the legal justification for drone strikes and said they should be subject to independent oversight.

The committee chides Obama for his failure to fulfil a commitment to close Guantánamo Bay. It notes that many detainees have been held there, and in military prisons in Afghanistan, for more than a decade without charge or trial. It call on the US to speed up the transfer of detainees and ensure that any criminal cases are dealt with by the US justice system rather than a military commission.

The committee also expressed alarm about the continued use of the death penalty in a 16 states, the "still high number" number of fatal shootings by certain police forces, notably in Chicago and the high proportion of black people in the country's jails.