Senator John Kerry will press Pakistani leaders for answers on Osama bin Laden in talks this week but he will be keen to ensure Pakistani anger over the raid does not subvert vital security cooperation.
U.S. special forces found and killed the al Qaeda leader in the garrison town of Abbottabad, 50 km (30 miles) north of Islamabad on May 2.
His discovery living comfortably in a high-walled compound virtually under the noses of military authorities has revived suspicion that Pakistani security agencies knew where he was all along.
Pakistan welcomed bin Laden's killing as a big step against militancy.
But the secret U.S. raid to get him has been condemned as a violation of sovereignty which embarrassed and outraged the military. Military officials say it has caused a breakdown in trust which has cast a shadow over security cooperation.
Pakistan might be tricky ally but it is vital to U.S. efforts to combat Islamist militants and to efforts to stabilize Afghanistan, where U.S. forces depend on Pakistani supply lines for water, food, fuel and other essentials.
In a sign of Pakistani anger, the chairman of Pakistan's joint chiefs of staff committee, General Khalid Shameem Wynne, on Friday canceled a five-day visit to the United States that had been set to begin on May 22.
But officials in Pakistan's civilian government said security cooperation with the United States would go on.
"There is difference of opinion but we'll continue our cooperation with the world as well as the United States," said one senior government official who declined to be identified.
The United States is likely to seek Pakistani help in an investigation into an imam of a Florida mosque and his two sons, arrested in the United States on Saturday on charges of financing the Pakistani Taliban.
Three others charged were living in Pakistan, U.S. officials said. Pakistan's Foreign Ministry said had yet to get a request for help but was ready to assist.
"As far as countering terrorism is concerned, there has been constant cooperation with the United States and there is no suspension of it," said ministry spokeswoman Tehmina Janjua.
Details of Kerry's visit have not been announced but media said he will be in Islamabad for talks on Monday.
Pakistan's parliament condemned on Saturday the U.S. raid to find and kill bin Laden, and called for a review of U.S. ties, warning that Pakistan could cut U.S. supply lines to its forces in Afghanistan if there were more such attacks.
Kerry has long been seen as a friend of Pakistan but told reporters in Afghanistan at the weekend that serious questions remained after the killing of bin Laden.
The United States wanted Pakistan to be a "real" ally in combating militants, and while it needed to improve its efforts, the death of bin Laden provided a critical chance to move forward, he said.
"We obviously want a Pakistan that is prepared to respect the interests of Afghanistan, and to be a real ally in our efforts to combat terrorism," Kerry told reporters in the northern Afghan city of Mazar-i-Sharif.
"We believe there are things that can be done better," he said. "But we're not trying to find a way to break the relationship apart, we're trying to find a way to build it."
The U.S. administration has not accused Pakistan of complicity in hiding bin Laden but has said he must have had some sort of support network, which it wants to uncover.
U.S. legislators have questioned whether Pakistan is serious about fighting militants and some have called for a suspension of U.S. aid.
Pakistan has rejected as absurd suggestions the killing showed incompetence or complicity in hiding the al Qaeda leader.
Kerry, a Democrat close to the Obama administration and who is chairman of the Senate Foreign Relations Committee, said earlier it was "extraordinarily hard to believe" bin Laden could have been in Pakistan for so long without any knowledge.
Asked if the United States would conduct a similar raid inside Pakistan to kill Mullah Omar, the reclusive leader of the Afghan Taliban, Kerry said Washington would consider all options.
Kerry, speaking a day after two suicide bombers killed 80 people at a Pakistani paramilitary academy, said Pakistan was a victim of extremism and faced its own tough decisions.
Pakistan has a long record of using Islamist militants as proxies, especially to counter the influence of nuclear-armed rival, India.