The legality of U.S. forces shooting an unarmed Osama bin Laden hinges on a highly contentious and long-debated question: Is anti-terrorism part of a military campaign or a law-enforcement effort?
In war, enemy combatants who don't explicitly surrender are considered legitimate targets, international experts said. Bin Laden's killing in a military context would be legal under the scenario officially put out by the White House Wednesday _ that bin Laden was unarmed but tried to resist being taken in.
In contrast, international human rights law dictates that police must use the greatest possible effort to capture suspects alive, barring direct threats to the lives of officers or civilians.
"There is a higher obligation not to use lethal force," said Andrea Prasow, senior counsel in Human Rights Watch's Terrorism and Counterterrorism Program.
"We don't have enough facts to know whether the killing was justified under international law," Prasow told AP. "We look forward to the U.S. government disclosing further information so we can understand exactly what happened. It may well have been a lawful killing in an armed conflict situation or it may have been a lawful killing in a law enforcement context."
The Obama administration strongly emphasized Wednesday that bin Laden's slaying by a Navy SEAL team was part of a legitimate military operation, with U.S. Attorney General Eric Holder telling the Senate Judiciary Committee that the shooting was justified as an action of "national self-defense" against a lawful military target. Noting that bin Laden had admitted his involvement in the events of Sept. 11 nearly a decade ago, he said, "It's lawful to target an enemy commander in the field."
The U.S. position appeared to strengthen during the day as U.S. officials told The Associated Press that the SEALs killed bin Laden after they saw him appear to lunge for a weapon.
The officials, who were briefed on the operation, say several weapons were found in the room where the terror chief died, including AK-47s and personal side arms.
International experts said there was widespread disagreement about whether al-Qaida members such as bin Laden are legitimate military targets.
The U.N.'s independent investigator on extrajudicial killings, Christof Heyns, said this week that there was "considerable dispute in legal circles as to whether we are dealing with an armed conflict in respect of al-Qaida in Pakistan."
The International Committee of the Red Cross was holding a meeting on the issue Thursday and declined to comment beforehand.
Louise Doswald-Beck, a former legal chief for the Red Cross said, however, that bin Laden was clearly not an enemy combatant.
"He was basically head of a terrorist criminal network, which means that you're not really looking at the law of armed conflict but at lethal action against a dangerous criminal," she said.
There has been virtually no discussion in international legal circles of launching an investigation into bin Laden's death that could result in the prosecution of anyone involved. In many countries, however, the debate about the legitimacy of the killing could influence perceptions about U.S. foreign policy.
Doswald-Beck, who teaches law at Geneva's Graduate Institute, said only an independent investigation of bin Laden's body would be able to prove exactly how he died, and that had been rendered virtually impossible by the destruction of forensic evidence when he was buried at sea.
A U.S. official said the burial decision was made after concluding that it would have been difficult to find a country willing to accept bin Laden's remains. There was also concern that a grave site could have become a rallying point for militants.
"I think questions should be asked as to why they dumped him at sea, because that makes it impossible to conduct an independent investigation," Doswald-Beck said.
The call for more information on the raid gained added weight with a statement from the U.N.'s top human rights official.
"This was a complex operation, and it would be helpful if we knew the precise facts surrounding his killing," said U.N. High Commissioner for Human Rights Navi Pillay. "The United Nations has consistently emphasized that all counterterrorism acts must respect international law."
At the time of his death, bin Laden was subject to U.N. sanctions including an asset freeze and travel ban.
After he was indicted in the U.S. for the August 1998 bombings of the U.S. embassies in Kenya and Tanzania, the Security Council in October 1999 adopted a resolution demanding that the Taliban turn him over "without further delay" to appropriate authorities in a country "where he will be arrested and effectively brought to justice."
On September 28, 2001 _ just over two weeks after the attacks on U.S. _ the council ordered all states to "ensure that any person who participates in the financing, planning, preparation or perpetration of terrorist acts or in supporting terrorist acts is brought to justice."
The U.S. government might point to several other provisions in that resolution to support its claim that bin Laden's killing was an act of self defense.
The resolution reaffirmed "the inherent right of individual or collective self-defense" recognized by the U.N. Charter and "the need to combat by all means, in accordance with the Charter of the United Nations, threats to international peace and security caused by terrorist acts." It was adopted under Chapter 7 of the U.N. Charter which means the resolution can be enforced militarily.
Associated Press writers Nedra Pickler and Mark Sherman in Washington and Edith M. Lederer at the United Nations contributed to this story.