There is no evidence Pakistani officials knew Osama bin Laden was living at a compound deep inside the country, but the United States is not ruling out the possibility, President Barack Obama's counterterrorism adviser said on Tuesday.

The death of the al Qaeda leader in Monday's U.S. raid on his compound in Abbottabad, a military garrison town 38 miles from the capital Islamabad, has led some U.S. lawmakers to demand a review of U.S. aid to nuclear-armed Pakistan.

"They (Pakistani officials) are expressing as great a surprise as we had when we first learned about this compound, so there is no indication at this point that the people we have talked to were aware of this, but we need to dig deeper into this," White House counterterrorism chief John Brennan said in an interview with National Public Radio.

In an opinion piece in the Washington Post, Pakistan's President Asif Ali Zardari said bin Laden "was not anywhere we had anticipated he would be" but he did not answer accusations his security services should have known of the hide-out.

When asked whether officials in Pakistan's military might have known about bin Laden's presence in the compound, Brennan said it was possible.

"I think it would be premature to rule out the possibility that there were some individuals inside of Pakistan, including within the official Pakistani establishment, who might have been aware of this, but we're not accusing anybody at this point."

Brennan said it appeared that bin Laden had lived for the past five to six years in the compound in Abbottabad, the site of an important Pakistani military academy.

Bin Laden was living in neighboring Afghanistan at the time of the al Qaeda September 11 attacks on the United States and when a subsequent U.S.-led invasion helped topple the Taliban government.

"Well I think the latest information is that he was in this compound for the past five or six years and he had virtually no interaction with others outside that compound. But yet he seemed to be very active inside the compound," Brennan said on the CBS Early Show program.

"And we know that he had released videos and Audis. We know that he was in contact with some senior al Qaeda officials," Brennan added.