WASHINGTON: The US-Pakistan security relationship has dipped to its lowest point since the September 11, 2001 attacks, threatening counterterrorism programs, The Washington Post reported Thursday.

US and Pakistan officials told the Post that the ties could deteriorate even further amid growing pressure from within the Pakistani military to reduce ties with the United States in the wake of last month's US Special Operations Forces raid that killed Osama bin Laden in Abbottabad.

The United States kept the raid secret, not informing Pakistan ahead of time, which left its military and intelligence frustrated and humiliated after the operation that also invited allegations of incompetence and complicity.

Pakistan's army chief, General Ashfaq Kayani, is “fighting to survive,” an unnamed US official told the newspaper. “His corps commanders are very strongly anti-US right now, so he has to appease them.”

The pressure on Kayani is unprecedented under Pakistan's strict military hierarchy.

“Nobody should underestimate the pressure he's now under,” another US official said.

Meanwhile, US lawmakers have been similarly displeased, complaining that Pakistani cooperation remains unreliable despite a huge US aid package that has totalled over $20 billion since 2001.

They have also denounced Pakistan's arrest of several Pakistani informants who provided intelligence to the CIA about bin Laden's compound.

According to the Post, one of those detained was Major Amir Aziz, a doctor in the Pakistani army's medical corps who lived next to bin Laden's Abbottabad compound.

He was said to have monitored who entered and left the residence, though the Pakistani military denied that any army officer had been detained over what it called the “Abbottabad incident”.

Meanwhile, the Pakistanis have pressured Washington to end its covert campaign of drone strikes in the country's lawless tribal areas bordering Afghanistan and a US Special Operations training program for Pakistan's tribal defence force has largely ended.

Pakistan has also withheld visas from CIA and military personnel.