Pakistan's army has admitted to "shortcomings" in its efforts to locate Osama bin Laden.

In a statement Thursday, the army also said U.S. military personnel in the country will be reduced to the "minimum essential" levels. The army statement gives no details, but it comes amid Pakistani anger over the American raid that killed bin Laden on Monday.

The statement warned that if the U.S. launches a similar raid in the future then the army and intelligence services will review their ties with Washington

It is the first response by the army since the raid. The army has been criticized for failing to locate bin Laden in a large compound in an army town not far from the capital Islamabad.

U.S. officials were not immediately available for comment.

Earlier Thursday, the Pakistan government warned the U.S. of "disastrous consequences" if it carried out any more unauthorized raids against suspected terrorists.

However, the government stopped short of labelling the helicopter raid on the al-Qaeda leader's compound as an illegal operation, and insisted relations between Washington and Islamabad remain on course.

Meanwhile, new details are emerging about the raid. A senior defence official said only one of the five people killed was armed and ever fired a shot. And the official says that shooter was killed in the early minutes of the commando assault, an account that differs greatly from original reports that portrayed a chaotic, prolonged firefight amid stiff resistance.

The official spoke Thursday on condition of anonymity because he was not authorized to speak on the record. The new details emerged after officials have had time to debrief the Navy SEALS who pulled off the raid in Pakistan.

He said the operation was a precision, floor-by-floor mission through bin Laden's compound where all of the others encountered were not carrying weapons and were quickly eliminated.

The army and government in Pakistan have come under criticism domestically for allowing the country's sovereignty to be violated.

Some critics have expressed doubts about Pakistani government claims that it was not aware of the raid until after it ended. Foreign Secretary Salman Bashir's remarks seemed to be aimed chiefly at addressing that criticism.

"The Pakistan security forces are neither incompetent nor negligent about their sacred duty to protect Pakistan," he told reporters.

"There shall not be any doubt that any repetition of such an act will have disastrous consequences," he said.

Bashir repeated Pakistani claims that it did not know anything about the raid until it was too late to stop it. He said the army scrambled two F-16 fighter jets when it was aware that foreign helicopters were hovering over the city of Abbottabad, but they apparently did not get to the choppers on time.

American officials have said they didn't inform Pakistan in advance, fearing bin Laden could be tipped off.

Asked whether it was illegal, Bashir said only "that is for historians to judge."

The fact that bin Laden was hiding in a large house close to an army academy in a garrison town two hours drive from the capital has led to international allegations that sections of Pakistan's security forces may have been harbouring bin Laden.

Pakistan has firmly denied those charges, but failed to explain how it did not know. Bashir said there were no plans for an investigation.

The warning from Pakistan comes a day after U.S. President Barack Obama said that photos of the dead al-Qaeda leader would not be released for the public to see.

Obama is travelling to Ground Zero in New York on Thursday, where he will meet privately with families of Sept. 11, 2001, victims and emergency workers.

With files from CBC News