ISLAMABAD, August 31, 2008 (AFP) - Two Chinese telecoms engineers have gone missing in northwest Pakistan along with their driver and a security guard, an embassy official and police said Sunday.

The group disappeared on Friday in restive North West Frontier Province near the border with Afghanistan, a senior diplomat at the Chinese embassy told AFP.

Police have sent three investigation teams to the rugged area in an attempt to trace the engineers and their entourage.

'We don't know whether someone has kidnapped them, they have lost their way or met an accident, because it is a mountainous area,' senior police official Khurshid Khan said.

The engineers, working for Zhongxing Telecommunication Equipment, were checking an installation in the area when they went missing.

Islamic militants have been known to target Chinese workers in Pakistan.

China is one of Islamabad's closest allies and its largest arms supplier.

In October 2004, Islamic militants led by a former Guantanamo Bay prisoner, Abdullah Mehsud, kidnapped two Chinese engineers working on a multi-million dollar hydroelectric dam project in the South Waziristan tribal area.

One of the hostages died in a botched rescue bid.

Mehsud died last year when he blew himself up to avoid arrest.

His brother, Baitullah Mehsud, is a leading Taliban commander in Pakistan's tribal regions who has been linked to a wave of suicide bombings following a deadly army raid on the Red Mosque in Islamabad in July 2007.