Pakistan will review its relationship with the United States in a high-level meeting on Sunday, the prime minister's office said, following the killing of the Pakistani Taliban leader in a US drone strike.
Mehsud, who had a $5 million US bounty on his head, was killed on Friday in the northwestern Pakistani militant stronghold of North Waziristan, near the Afghan border. The Pakistani Taliban have killed thousands of Pakistani civilians and members of the security forces in their bid to impose Islamist rule but the new government has been calling for peace talks.
The government denounced Mehsud's killing as a US bid to derail the talks and summoned the US ambassador on Saturday to complain. "The murder of Hakimullah is the murder of all efforts at peace," said Interior Minister Chaudhry Nisar, adding that the government still wanted to pursue talks. Some politicians have demanded that US military supply lines into Afghanistan be blocked in response to the US attack.
Pakistan is the main route for supplies for US troops in landlocked Afghanistan, for everything from food and drinking water to fuel, and the closure of the routes could be a serious disruption as US and other Western forces prepare to withdraw from Afghanistan by the end of next year.
Pakistani cooperation is also seen as vital in trying to bring peace to Afghanistan, in particular in nudging the Afghan Taliban, who are allied but separate from the Pakistani Taliban, into talks with the Kabul government.
Relations between the United States and Pakistan have been seriously strained several times over recent years, including in 2011, when US forces killed Osama bin Laden in a raid that Pakistan said violated its sovereignty.
Despite its anger, cash-strapped Pakistan depends to a great extent on US support and the United States, despite frustrations over the relationship, is unlikely to ever make a complete break with its nuclear-armed ally.
Three Pakistani Taliban commanders said they had been due meet a government delegation on Saturday and they had been meeting to discuss the talks. They said they felt betrayed by Mehsud's killing and were not interested in talks. A Pakistani Taliban spokesman vowed a wave of revenge bombings.
Mehsud's followers have been debating who should replace him. Several militant commanders said on Saturday that 38-year-old Khan Said, known as Sajna, had been chosen.
But other factions of the Pakistani Taliban alliance were unhappy with the choice and were supporting other candidates, including Mullah Fazlullah, the ruthless commander from the Swat Valley, northwest of the capital, Islamabad, whose men shot and wounded schoolgirl Malala Yousafzai last year.
Said was seen as a relative moderate and if he became leader, talks with the government might eventually get going, said Imtiaz Gul, head of Islamabad-based Centre for Research and Security Studies think-tank. But if Fazlullah was chosen, there would be little hope of compromise, he said.
Even if talks started, it was unclear how successful they would be unless the government gave significant concessions to the militants, Gul said. "You're compromising the rule of law, and ceding ground to non-state actors, giving in to a small band of criminals. It threatens everything on which Pakistan stands - the constitution, parliament," Gul said.
"They haven't thought through the consequences of these talks. They're just firefighting because they have no long-term remedy for Pakistan's problems." While the government has been promoting talks, the powerful Pakistani military has voiced its opposition to negotiating with the al Qaeda-linked militants.