Peshawar: Pakistan shut down the main land route for NATO supplies into Afghanistan on Thursday after officials accused NATO of killing three Pakistani troops in the fourth cross-border attack this week.
NATO and the Pakistani government said they were investigating the reported incident in the Kurram district of Pakistan`s tribal belt, which Washington has branded an al Qaeda headquarters and hub of militants fighting in Afghanistan.
"We have suspended NATO supply trucks for the time being due to security reasons," an official in Pakistan`s Frontier Corps paramilitary unit said in the northwestern city of Peshawar on condition of anonymity.
Two officials at the Torkham border crossing in Pakistan`s northwestern Khyber district and a US diplomat confirmed that NATO convoys were not being allowed to cross.
Khyber is on the main NATO supply route through Pakistan into Afghanistan, where more than 152,000 US and NATO forces are fighting a nine-year Taliban insurgency.
Pakistan has condemned cross-border air strikes by NATO helicopters pursuing militants into its territory. NATO said it was investigating Thursday`s incident, but has said previously it has the right to self-defence.
Washington considers Pakistan`s border areas with Afghanistan the most dangerous place on Earth and has this month significantly stepped up a covert drone war on Taliban and al Qaeda-linked militants holed up in the area.
Although Pakistan is a key US ally, its powerful military has been accused in the West of playing a double game in supporting Afghan Taliban.
Pakistani security officials said that NATO helicopters had entered Pakistani airspace and bombed a paramilitary checkpoint in an "unprovoked attack" in Mandati Kandaw village.
"NATO helicopters entered our airspace and targeted a paramilitary checkpost killing three soldiers and wounding three others," one official said.
"NATO helicopters intruded up to five kilometres (three miles) into Pakistan`s airspace," the Pakistani official said.
ISAF said it was investigating the Pakistani claims, saying that an air strike had targeted insurgents "believed" to have been on the Afghan side of the border and denying that its troops crossed into Pakistan airspace.
"Early this morning, a coalition force observed what they believed was a group of insurgents attempting to fire mortars at a coalition base in the border area of Dand Patan district, Paktiya province," it said. "A coalition air weapons team was called for fire support and engaged the insurgents."
After being informed by Pakistanis that their border forces had been hit, ISAF said it was working with the Pakistanis "to ascertain if the two events are linked".
"The matter remains under investigation," it said.
Pakistan`s civilian government also said it was investigating and stopped short of confirming what it called "reports".
"Let the investigation complete first, then we will formulate our response," foreign ministry spokesman Abdul Basit told reporters.
It was the fourth such attack reported in a week.
The US’ presence in Afghanistan and US drone strikes in the tribal belt are the subject of fierce criticism and suspicion in Pakistan.
On Monday, the government in Islamabad denounced cross-border NATO air strikes as a violation of its sovereignty.
The Pentagon said on Tuesday the recent strikes were marked by "communication breakdowns" as allied officers were not able to contact their Pakistani counterparts about the operation until afterwards.
ISAF said helicopters pursued insurgents in Pakistan on Friday after an Afghan security force outpost in Khost province came under attack.
It said 30 rebels were killed and that two helicopters returned to the border area on Saturday, killing several more.
Pakistani security officials then said that five people were killed by NATO cross-border fire on Matta Sanga town on Monday.