At least 18 passengers in a convoy of vans have been killed by unknown gunmen in southwestern Pakistan.

Eyewitnesses report that an Iran-bound buss, which began its journey from Karachi, was attacked in Khadan area of Turbat.

Eyewitnesses said the gunmen, who were lying in wait, opened fire at the vehicle as it came in the firing range and kept shooting until their automatic weapons were depleted of ammunition. They then made their escape on motorcycles.

The attack occurred when the bus stopped at a roadside shop in the Kech area of Baluchistan province, the police said. They said six gunmen were involved.

The dead and the injured were being taken to the Civil Hospital.

Drone strike

Elsewhere in Pakistan, a triple drone strike strike in North Waziristan is reported to have killed at least 21 people.

According to official sources, six missiles were fired from a US drone at a compound in Gharlamay village of Datta Khel town near the border with neighbouring Afghanistan.

Security officials identify the dead as "militants".

It was the first drone attack since Islamabad reached a deal with Washington to reopen land routes into Afghanistan after US Secretary of State Hillary Clinton said she was sorry for the deaths of 24 Pakistani soldiers in an air strike in November.

A similar attack in the region on Sunday killed six extremists.

The initial strike on a house killed nine, three others were killed in a second attack when they drove to the site to recover dead bodies, and a third drone killed another three five minutes later, a senior security official in Peshawar told the AFP news agency.

Datta Khel is considered a stronghold of Hafiz Gul Bahadur, a Taliban commander accused of sending fighters across the border to fight NATO troops in Afghanistan.