|Nato trucks have been torched since Pakistan closed a key border crossing into Afghanistan [AFP]
Armed men in Pakistan have burned 22 tankers carrying fuel for Nato forces in Afghanistan, killing a lorry driver, according to police.
Shah Nawaz Khan, a police official, said on Wednesday that the attack, the latest on supply convoys since Pakistan closed a key border crossing to Nato forces last week, occurred in the parking lot of a roadside hotel on the outskirts of the southwest city of Quetta.
The attacks have raised tensions already elevated by Pakistan's decision to close the Torkham crossing in an apparent protest against alleged Nato helicopter strikes on its territory. One of those strikes killed three Pakistani soldiers.
The latest attack on fuel tankers took place along another route that remain open.
Nato incursions and the border closure have raised tensions between the United States and Pakistan, whose long alliance has often been strained.
Pakistan has repeatedly said it is doing all it can to fight terrorism, pointing to the thousands of people it has lost in a wave of attacks over the past three years. It has, however, said it will not tolerate any incursions by foreign troops into its territory.
The Pentagon said on Tuesday that Nato will soon release the results of a joint investigation with Pakistan into last week's killing of the Pakistani soldiers.
Geoff Morrell, Pentagon press secretary, did not elaborate on the findings but appeared to play down the likelihood of any major revelations. He described the helicopter strike as a "regrettable mistake".
The incident occurred in Pakistan's western Kurram region, when Nato forces were investigating what appeared to be a new Taliban fighting position along the border, Morrell said. "I guess they came under fire while they were checking out that position," he added.
Wednesday's attack came as Pakistan's US envoy said that increased US drone strikes in Pakistan's tribal areas, which have sparked widespread anger due to civilian deaths, are linked to a terror plot targeting Europe.
Hussein Haqqani, Pakistan's ambassador to the US, told the BBC that the surge in strikes in North Waziristan, a reputed hotbed for anti-government fighters, came after intelligence agencies uncovered a plot to "attack multiple targets in Europe".
He also said that a strike on Monday in Mir Ali Bazaar which killed eight fighters, including five Germans, was linked to the plot.
"I think that the activity we see in North Waziristan in terms of strikes ... is connected to the terrorist warnings that we have heard about potential strikes in Europe," Haqqani told the British broadcaster.
According to reports, an al-Qaeda plot planned in Pakistan is targeting Britain, France and Germany but planning for the attacks was at an early stage when intelligence agencies learned of them.
Japan, Sweden, the United States and Britain have warned their citizens travelling in Europe of the possibility of a terrorist attack.
Haqqani urged people to stay calm and vowed intelligence agencies would foil any plot.
"We do not want anybody to panic, there shouldn't be any panic because European, Pakistani and American intelligence services are working together to foil these plots," he added.
"Pakistan has been concerned about the presence of terrorists inside Pakistan or in the regions close to Pakistan for a long time and we have been working very hard at eliminating them."
US drone strikes have increased in recent weeks, with Pakistani authorities reporting 24 attacks since September 3 which have killed more than 140 people.