Image caption The US has insisted the action was lawful

Osama Bin Laden's death may come to be seen as a precedent for "targeted killings" by states in the future, a report written for MPs has suggested.

The report, prepared by the House of Commons library, says the former al-Qaeda leader's killing has "significant implications" for how the US and other countries deal with terrorist suspects.

Such methods could be seen to be "accepted politically", it argues.

The US argues it was lawful but critics say he should have been taken alive.

Prime Minister David Cameron and Labour leader Ed Miliband both said the demise of Osama Bin Laden during a raid on his Pakistani compound earlier this month, had made the world a safer place without him and it was a significant step in the fight against global terrorism.

Wider implications

But questions have been asked about the legality of the US special forces mission after it emerged, contrary to initial claims by the White House, that although its operatives came under sustained fire Bin Laden was not armed at the time he was shot.

An internal report for MPs written by parliamentary staff, analysing the legal arguments surrounding the action and its repercussions, has been published.

It says many of the outstanding legal questions are only likely to be resolved if the White House releases the instructions given to the US Navy Seals who carried out the operation and discloses what efforts were made to get Bin Laden to surrender and what threat he was believed to pose at the time.

But it says the killing could have a major impact on how states deal with al-Qaeda operatives and other terrorist suspects in future.

"The nature of Bin Laden's killing may be a sign the US is increasingly likely to kill rather than to capture al-Qaeda members," it states.

"A wider implication is that the killing may be seen as a precedent for targeted killings of individuals by any state, across international boundaries, at least where terrorism is involved..The more states act in this way, the more likely it is to become accepted, at least politically if not as a matter of international law."

'Self-defence'

The death of Bin Laden could also have implications for the coalition's military strategy in the Libya conflict, it adds, as "some of the arguments used to present Bin Laden's killing as lawful could also be applied if coalition forces kill Colonel Gaddafi".

The UK and its allies have repeatedly stressed the United Nations mandate they are working under does not authorise the targeting of the Libyan leader.

However, they say command and control facilities - including compounds used by the Gaddafi family and other senior regime members - are legitimate targets if they are being used to direct attacks against civilians.

The Obama administration has said Bin Laden was a "lawful military target" and the raid was justified as an action of "national self-defence".

It says Bin Laden was still actively leading al-Qaeda and that he had made "no attempt to surrender".

Among those who have expressed reservations about the killing include the Archbishop of Canterbury who said it was "uncomfortable" and "did not look as if justice" was "seen to be done".