Pakistani authorities have asked the Doctors Without Borders (MSF) aid group to close its medical facilities in a militancy-wracked tribal district, the organisation said, as officials tighten controls on foreign NGOs working in the country.

MSF said the government has refused to renew the permit required to continue its healthcare projects in Kurram district in the Federally Administered Tribal Areas (Fata) located in the restive northwest along the Afghan border.

"MSF is saddened by the decision from the authorities responsible for NGOs working in Kurram Agency," Catherine Moody, the group's country representative, said in a statement released late Wednesday.

The tribal districts are among the poorest areas in Pakistan, and are governed under a draconian legal system introduced by British colonial rulers more than a century ago.

A senior government official in Kurram confirmed that MSF has been asked to stop working in the district after its permit expired.

"They have been asked to stop working until their (permit) is renewed," the official told AFP Thursday, adding that authorities have been paying closer attention to foreign NGOs across the country, especially in tribal areas.

The organisation said officials have not explained why their permit was refused in an area where it has been providing healthcare for 14 years.

Although violence in Pakistan and its tribal districts has declined in recent years following a series of military offensives against insurgents, Kurram has remained a top target for militant groups.

Parachinar, the capital of the mainly Shiite Kurram tribal district became a scene of carnage in June when twin blasts ripped through a crowded market days ahead of Eid celebrations marking the end of Ramadan, killing 69 people and wounding more than 200.

The attack was the third major bombing to strike the area since January, with 115 people killed in total - the highest in Pakistan.

Inhabitants in the tribal belt have long complained its development and security has been neglected by Islamabad, which also appoints administrators with sweeping powers including the prerogative to collectively punish entire clans for the crime of an individual.

MSF has been working in Kurram since 2004 where it was responsible for an outpatient department for children under five years and an inpatient department for severely ill children up to 12 years of age.

"We will, as much as possible continue to provide obstetric and newborn services to the women of Fata through the MSF women's hospital located in Peshawar," the statement said.

The group has a long history in Pakistan, working with communities affected by natural disasters, conflicts and insufficient healthcare facilities for over 30 years.