US President Barack Obama ordered that the team sent to raid Osama bin Laden's compound be large enough to fight off Pakistani forces should they intervene, the New York Times reported.
Citing unnamed officials, the paper said Obama raised the prospect of a clash 10 days before the May 1 raid, resulting in an extra two fighter helicopters being sent to protect the commandos raiding the compound.
"Some people may have assumed we could talk our way out of a jam, but given our difficult relationship with Pakistan right now, the president did not want to leave anything to chance," it quoted a senior official as saying.
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"He wanted extra forces if they were necessary."
The Times also reported that two teams of specialists were on standby for the mission: one to bury the Al-Qaeda leader if he were killed, and another made up of lawyers, interrogators and translators in case he was captured.
It said the latter team was likely aboard the aircraft carrier Carl Vinson in the North Arabian Sea.
Bin Laden was buried at sea after he was shot dead in the raid, officials have said.
The latest revelations come at a time of heightened tensions between the two military allies, with Pakistan slamming the US operation and denying what it called "absurd" allegations that it was sheltering the world's most wanted man.
Islamabad has also vowed to retaliate against any similar operations.
Washington in turn has emphatically refused to say sorry for taking out its enemy Number 1, blamed for masterminding the September 11, 2001 attacks in which almost 3,000 people were killed.
