By Saud Mehsud and Hafiz Wazir

DERA ISMAIL KHAN/WANA, Pakistan (Reuters) - Pakistani Taliban fighters secretly buried their leader on Saturday after he was killed by a U.S. drone aircraft and quickly moved to replace him while vowing a wave of revenge suicide bombings.

The Pakistani government denounced the killing of Hakimullah Mehsud as a U.S. bid to derail planned peace talks and summoned the U.S. ambassador to protest. Some lawmakers demanded the blocking of U.S. supply lines into Afghanistan in retaliation.

"The murder of Hakimullah is the murder of all efforts at peace," said Interior Minister Chaudhry Nisar. "Americans said they support our efforts at peace. Is this support?"

Mehsud, who had a $5 million U.S. bounty on his head, and three others were killed on Friday in the militant stronghold of Miranshah in northwest Pakistan.

Mehsud's vehicle was hit after he attended a meeting of Taliban leaders, a Pakistani Taliban fighter said, adding that Mehsud's body was "damaged but recognizable". His bodyguard and driver were also killed.

He was secretly buried under cover of darkness in the early hours by a few companions amid fears that his funeral might be attacked by U.S. drones, militants and security sources said.

"Every drop of Hakimullah's blood will turn into a suicide bomber," said Azam Tariq, a Pakistani Taliban spokesman.

"America and their friends shouldn't be happy because we will take revenge for our martyr's blood."

Mehsud took over as leader of the al Qaeda-linked Pakistani Taliban in 2009. The group's two previous leaders were killed in attacks by U.S. missile-firing drones.

Taliban commanders said they wanted to replace him with the movement's number two, Khan Said, who is also known as Sajna.

Said is believed to have masterminded an attack on a jail in northwest Pakistan that freed nearly 400 prisoners in 2012 and a big attack on a Pakistani naval base.

But some commanders were unhappy with the choice and wanted more talks, several militants said, indicating divisions within the Pakistani Taliban, an umbrella group of factions allied with the Afghan Taliban and battling the Pakistani state in the hope of imposing Islamist rule.

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The Pakistani Taliban killed an army general in September, has beheaded Pakistani soldiers and killed thousands of civilians in suicide bombings. The group also directed a failed attempt to bomb Times Square in New York.

In 2010, Mehsud appeared in a farewell video with a Jordanian suicide bomber who killed seven CIA employees at a base in Afghanistan.

"ATTACK ON TALKS"

Mehsud was in his mid-30s and had a sharp face framed by a beard and a tangle of long hair, usually flowing from beneath a traditional Afghan hat.

Despite his reputation as an uncompromising commander, Pakistan's new government had vowed to try to stop the violence through peace talks and it reacted angrily to his death.

"The U.S. has tried to attack the peace talks with this drone but we will not let them fail," said Information Minister Pervez Rashid. The Taliban said on Friday those negotiations had yet to start.

The Pakistani foreign office said in a statement on Saturday Mehsud's death was "counter-productive to Pakistan's efforts to bring peace and stability to Pakistan and the region".

Shah Farman, a spokesman for the government of the northwestern province of Khyber Pakhtunkhwa, said provincial lawmakers would pass a resolution on Monday to cut NATO supply lines into landlocked Afghanistan. A major one passes through the nearby Khyber Pass.

The supply lines through U.S. ally Pakistan have been crucial since the latest Afghan war began in 2001 and remain vital as the United States and other Western forces prepare to withdraw from Afghanistan by the end of next year.

Residents of Miranshah, the capital of the North Waziristan region on the Afghan border, said Pakistani Taliban fighters were converging on the town and firing furiously at drones buzzing high in the sky.

About eight drones were seen overhead as well as a larger aircraft that seemed to be an aeroplane or a type of drone that residents said they had not seen before.

"We thought it was a C-130 aircraft but it was a special spy plane, bigger in size," resident Farhad Khan said by telephone from Miranshah. "The militants fired from their anti-aircraft guns to hit it but couldn't."

Shops and markets were open in the town. Residents said they were worried about a possible army offensive but not Taliban reprisals. They expected the militants to launch attacks elsewhere in Pakistan.

"We feel the militants will show their reaction in major cities like they usually do," said resident Assadullah Dawar.

In May, Mehsud's deputy was killed by a drone nearby. Last month, one of his top deputies was captured in Afghanistan.

(Additional reporting by Jibran Ahmad in Peshawar; Writing by Katharine Houreld; Editing by Gareth Jones)