UN human rights investigators called on the United States on Friday to disclose the full facts surrounding the killing of Osama bin Laden, in particular whether there had been any plan to capture him.
Christof Heyns, UN special rapporteur on extrajudicial, summary or arbitrary executions, and Martin Scheinin, special rapporteur on protecting human rights while countering terrorism, said that in certain exceptional cases, deadly force may be used in "operations against terrorists".
"However, the norm should be that terrorists be dealt with as criminals, through legal processes of arrest, trial and judicially-decided punishment," the independent experts said in a joint statement.
"In respect of the recent use of deadly force against Osama bin Laden, the United States of America should disclose the supporting facts to allow an assessment in terms of international human rights law standards," they said.
"It will be particularly important to know if the planning of the mission allowed an effort to capture bin Laden."
It was important to get this information "into the open," according to the investigators who report to the UN Human Rights Council whose 47 members include the United States.
A US acknowledgment that bin Laden was unarmed when shot in the head in its operation at his hideout in Pakistan on Monday - as well as the sea burial of his body, a rare practice in Islam - have drawn some criticism in the Arab world and Europe, where some have warned of a backlash.
Navi Pillay, the top UN human rights official, also called on Tuesday for light to be shed on the killing, stressing that all counter-terrorism operations must respect international law.
"We've raised a question mark about what happened precisely, more details are needed at this point," her spokesman Rupert Colville told a briefing in Geneva on Friday.
He was not aware that Pillay's office had had any contact with US authorities on the issue this week.