Islamabad, Pakistan (CNN) -- Pakistanis passed along raw phone-tap data to the United States that eventually led to Osama bin Laden's killing, but they failed to analyze or interpret the information themselves, a Pakistani intelligence official told CNN.
The details of what Pakistanis did or didn't know or do about the daring American operation to kill bin Laden -- from intelligence gathering to the execution of the raid -- remained unclear Monday.
But the intelligence official said that information about bin Laden and the people in the compound where he stayed "slipped from" Pakistan's "radar" over the months.
The intelligence official said Pakistan regularly passed along intelligence of interest to Americans.
The official did not say over what period the data was collected, but noted that from September the United States "was concentrating on this."
He added that much of the focus was on a courier coming and going to the compound. He did not give the courier's nationality or name.
Osama bin Laden was not in contact with other militant networks while he was there and maintained "an invisible footprint," the official said.
Of the raid, he said, "I think they came in undetected and went out the same day."
He added Pakistan officials do not think there were any U.S. intelligence personnel on the ground ahead of the special operations forces.
There has been improving cooperation between Pakistan and the United States on security matters.
But there have been concerns among Americans over the reliability of Pakistan's intelligence apparatus in the ongoing war on terror, particularly the links of Pakistan's Inter-Services Intelligence operations to militants in the country's tribal region and across the nation.
Many Pakistanis have been enraged over the drone strikes against militants in the tribal region, strikes said to be conducted by the United States.
The United States says it didn't share intelligence with or a give a heads-up to Pakistan about the planned raid on the compound where U.S. military personnel in a raid with helicopters killed Osama bin Laden.
"We shared our intelligence on this bin Laden compound with no other country, including Pakistan," a senior U.S. administration official told CNN.
"That was for one reason and one reason alone: We believed it was essential to the security of the operation and our personnel. In fact, only a very small group of people inside our own government knew of this operation in advance," the official said.
Shortly after the raid, U.S. officials contacted senior Pakistani leaders to brief them on the intent and the results of the operation, the official said.
Pakistan's ambassador to the United States said both countries "cooperated in making sure" that the operation leading to bin Laden's death was "successful."
Husain Haqqani said on CNN's "American Morning" that President Barack Obama called Pakistan's president to thank him for Pakistan's cooperation.
He said that if Pakistan had known where bin Laden was it would have pursued him.
"We are very glad that our American partners did," he said. "They had superior intelligence, they had superior technology, and we are grateful to them and to God for having given us this opportunity to bring this chapter to an end."
Wajid Shamsul Hasan, Pakistan's high commissioner to the United Kingdom, told CNN Pakistan knew the operation was going to happen but he was unclear when it was informed about it.
He said both Pakistan and the United States shared intelligence, and Pakistan was "in the know of certain things" and "what happened happened with our consent."
"Americans got to know him -- where he was first -- and that's why they struck it and struck it precisely," he said.
One Pakistani official told CNN on Monday that the operation was American, and that Pakistan "assisted only in terms of authorization of the helicopter flights in our airspace." He asked not to be named because he was not authorized to speak about the issue.
"In any event, we did not want anything to do with such an operation in case something went wrong," the official said.
In his announcement of the raid, Obama said that "U.S. counterterrorism cooperation with Pakistan helped lead us to bin Laden and the compound where he was hiding." He said he called President Asif Ali Zardari and his "team" spoke to their Pakistani counterparts.
"They agree that this is a good and historic day for both of our nations."
The government of Pakistan said in a statement that the "operation was conducted by the U.S. forces in accordance with declared U.S. policy that Osama bin Laden will be eliminated in a direct action by the U.S. forces, wherever found in the world."
"Osama bin Laden's death illustrates the resolve of the international community including Pakistan to fight and eliminate terrorism. It constitutes a major setback to terrorist organizations around the world," it said.
The government said Pakistan "has played a significant role in efforts to eliminate terrorism" and has had "extremely effective intelligence-sharing arrangements with several intelligence agencies including that of the U.S."
"It is Pakistan's stated policy that it will not allow its soil to be used in terrorist attacks against any country. Pakistan's political leadership, parliament, state institutions and the whole nation are fully united in their resolve to eliminate terrorism," it said.
CNN's Peter Bergen contributed to this report