The U.S. said on Thursday the killing of Osama Bin Laden was not an assassination and that the U.S. Navy SEALs who stormed his hideout and killed him were on a 'kill or capture' mission.

If the possibility had existed, if there was the possibility of a feasible surrender, that would have occurred, U.S. Attorney General Eric Holder told BBC News.

Legal opinion has been divided over the legality of the killing of Bin Laden as some experts said the action contravened international norms.
However, from the very beginning the U.S. held on to the argument that Bin Laden was an enemy combatant and not a political foe. The killing of a political opponent is illegal according to international laws, and can be termed assassination.

Holder had said immediately after the killing of bin Laden that the U.S. considered him as a terrorist who waged war on the country and that his elimination was an 'act of national self-defense

... the operation in which Osama bin Laden was killed was lawful, legitimate and appropriate in every way. He was the head of al Qaeda, an organization that conducted the attacks of Sept. 11. He admitted his involvement, Holder told Congress.

On Thursday, Holder said the safety and protection of the commandos were of paramount importance in the operation. It is unclear if Obama was armed or if he offered to surrender, but according to Holder, while the SEALs would have been prepared to accept a surrender, their safety and the success of the operation were of the greatest importance.

But their protection, that is the protection of the force that went into that compound, was I think uppermost in our minds, he said.

Holder had also said last week that it wouldn’t have mattered much if Bin Laden was unarmed. Someone considered as enemy combatant is a legitimate target even if he is not armed. He explained that lethal force was permitted against enemy commanders in an ongoing battle.

Bin Laden had openly declared war on the U.S. and carried out the biggest attack in its soil in history.