Washington: The US will not offer any apology to Pakistan for its unilateral military action against Osama bin Laden, the White House said, adding he was ‘enemy number one’ for America.

The White House, however, acknowledged that Pakistan provided useful intelligence and cooperation over the years and assistance that helped the US build the ‘data’ that it needed to build in order to find the al- Qaeda chief and execute the mission in Abbottabad.

The Obama Administration also termed US' relationship with Pakistan as ‘complicated but important’ and assured that it is working on its ties with that country which received a setback after a secretive operation to kill the 9/11 mastermind on Monday.

"We make no apologies about that," White House Press Secretary Jay Carney said when asked whether the US should have gone unilaterally inside Pakistan to get bin Laden. He was enemy number one for these country and killed many innocent civilians." Carney said.

Pakistan on Tuesday termed the US commando operation that killed Laden an ‘unauthorised, unilateral action’ without its knowledge.

Besides, the White House said America has never been at war with Islam.

Taking action against bin Laden does not mean that one shouldn't be entirely respectful of Islam, which the US is. Carney said Laden was a relic of the past, in many ways.

CIA Director Leon Panetta also briefed members of the Congress on the successful operation during which he is believed to have said the US did not inform Pakistan as he believed that any information provided them to could be leaked and thus jeopardize the sensitive information.

Identifying Pakistan as a key partner in the fight against al Qaeda and terrorism, he said they have been extremely helpful and the US looks forward to cooperating into the future.

US-Pak ties turning sour on Osama

The Obama Administration's move to seek explanation from Pakistan on the type of support system al-Qaeda chief Osama bin Laden enjoyed there has resulted in heightened tensions between the two countries, media reports said.

In its lead story, a daily said the Obama administration officials here and in Islamabad demanded that Pakistan should quickly provide answers to specific questions about bin Laden and his years-long residence in Pakistani city.

It said top Pakistani officials have strongly denied that Islamabad tried to harbour Laden, and American officials said at this point there was no hard evidence that any Pakistani officials visited the compound in Abbottabad, or had any direct contacts with Laden.

"The US-Pakistani relationship has seemed to be spiraling downward for some time. Now, after Obama's announcement of bin Laden's death, it is in serious trouble," said noted Pakistani scholar Shuja Nawaz in an article in the Foreign Affairs magazine.

"If it was not, the raid was yet one more example of the deep distrust between the United States and Pakistan and may reflect poorly on latter's ability to defend its air space against such intrusions," Nawaz said.

US Congress up in arms against Pak

Lawmakers in the United States are up in arms against Pakistan with a  Congressman announcing a decision to introduce legislation to bar all aid to Islamabad till it demonstrated that it had no inkling of bin Laden's whereabouts.

The Pakistan Foreign Aid Accountability Act would require the State Department to certify to Congress that Pakistan was not providing a sanctuary for the world's most wanted terrorist.

"Pakistan has a lot of explaining to do. It seems unimaginable that Osama bin Laden was living 1,000 yards away from a military base in a million dollar mansion built especially for him and no one in the Pakistani government knew about it. I don't buy it," said Congressman, Ted Poe from Texas, who is proposing the legislation.

They now want White House to adopt a tough approach against Islamabad saying that over the years Pakistan has become the nerve centre of terrorism, he added.

And we now know that bin Laden was there up to six years," said Senator Dianne Feinstein, chairwoman of the Senate Intelligence Committee.

Peter T King, a top New York Congressman said he has been discussing this issue with people over the last several days and on Tuesday he met the Pakistani Ambassador to the US, Husain Haqqani.

(Agencies)

READ MORE: Osama was unarmed when killed: US

READ MORE: Laden hailed as martyr at Khartoum rally