Some US lawmakers believe Osama bin Laden presence in Pakistan may have frayed ties with the United States beyond repair, US Senator John Kerry told Islamabad on Monday, but added that their strategic relationship was too important to let go.
Washington's already fragile ties with ally Islamabad took a beating after US special forces flew in from Afghanistan on a secret operation to find and kill bin Laden on May 2, nearly 10 years after he orchestrated the Sept 11 attacks on the United States.
His discovery holed up in the comfortable garrison town of Abbottabad, only 50 km (30 miles) from the Pakistani capital, has deeply embarrassed Pakistan's military and spy agency and revived suspicion that Pakistan knew where he was and has been playing a double game.
Pakistan has rejected that as absurd, and its parliament has condemned the US raid as a violation of its sovereignty and called for a review of ties.
Kerry, a Democrat close to the Obama administration who is also chairman of the Senate Foreign Relations Committee, told Pakistan the United States has "grave concerns" that bin Laden was found in Pakistan, and that Congress was now scrutinising Washington's ties with its strategic ally.
But he also said both nations had to find a way to restore the trust between them, adding that US-Pakistan ties were "too important to be stuck speculating".
"I emphasised to our Pakistani friends - and they are friends - that many in Congress are raising tough questions about our ongoing economic assistance to the government of Pakistan because of the events as they unfolded, and because of the presence of Osama bin Laden in Pakistan," Kerry said.
"The make or break is real. There are members of Congress who are not confident it (ties) can be patched back together."
Compounding Pakistan's reputation as an unstable Muslim country infested with militants, gunmen on motorcycles shot dead a Saudi diplomat in the city of Karachi as he was driving to work.
Al Qaeda-linked Pakistani Taliban militants, who have vowed to strike back for the killing of Saudi-born bin Laden, claimed responsibility.
Kerry arrived in Pakistan on Sunday from Afghanistan, where he told reporters the United States wanted Pakistan to be a real ally in the fight against militancy.
Fewer than 100 al Qaeda members remain inside Afghanistan, the second-most senior US commander in the country said on Monday in Kabul, but those fighters act as a "cadre" organisation for the Afghan Taliban providing resources and technical battlefield skills.
US Lieutenant General David Rodriguez also said it was too early to say if the death of Osama bin Laden had an impact on the Taliban or if it would affect a gradual US troop drawdown due to begin in July.