Eight Pakistani employees of a US-based aid organisation are missing and feared kidnapped in Pakistan's volatile southwest bordering Afghanistan, a senior Pakistani government official said.

The employees of The American Refugee Committee (ARC) were returning after distributing food items from an Afghan refugee camp in Pishin, 50km from Quetta, the capital of Balochistan province, on Monday evening when they went missing.

"They distributed some relief goods among the refugees and were probably kidnapped on their way back to Quetta," Mansoor Kakar, Pishin's deputy commissioner, told Reuters.

Security forces launched a search operation in the refugee camp and other suspected areas. No one has claimed responsibility as yet.

Kakar said it was not clear who was behind the possible kidnapping: "We don't have any clue so far. Efforts are underway to recover them."

Armed groups linked to al-Qaeda and the Taliban, as well as ethnic Baloch armed groups fighting for more autonomy, have been involved in violence in the region, which also borders Iran.

Kidnapping is an industry in Pakistan's lawless tribal regions, with money often the main motivation rather than political demands.

Ransoms are a large source of revenue for the Taliban, al-Qaeda and Baloch fighters.

ARC has worked in refugee camps near Quetta since 2002, focusing on providing healthcare and training members of the community in basic health services, according to the ARC website.

It began operating in northern parts of Pakistan after the devastating earthquake in 2005.

Earlier this month, a Swiss couple was kidnapped by gunmen in the district of Loralai in Balochistan. They have not yet been recovered.

An American official of the UN refugee agency was kidnapped in Quetta in 2009 but was released after two months.

Source: Agencies