No one immediately claimed responsibility, but criminal gangs have often targeted foreign aid workers in the hope of securing large ransoms for their release.

"Health programme manager Khalil Rasjed Dale, a British national, was on his way home from work in a clearly marked ICRC vehicle when he was seized some 200 metres away from an ICRC residence," the ICRC said in a statement.

"The ICRC currently has no indication as to the abductors' identities or motives... Despite the incident, the ICRC will be continuing its humanitarian work in Pakistan."

Quetta is capital of southwestern Baluchistan, Pakistan's biggest but poorest province, where Baluch separatist militants are fighting a protracted insurgency for more autonomy and control over the area's natural resources.

Pro-Taliban militants are also active in the province, which shares borders with Afghanistan and Iran. Four health workers, including two doctors, were kidnapped by militants last week from the Pishin area of Baluchistan, near Quetta. They were freed after a shootout between police and their kidnappers.

The Geneva-headquartered ICRC, which has had a permanent presence in Pakistan since 1981, also said it was scaling down its work in the country and closing six of its 10 offices.

The move was not due to Thursday's kidnapping, officials said, but due to "operational difficulties."

"The main reason we are scaling down is because of increasing difficulties in accessing certain areas and populations," said Narej Resich, ICRC communications delegate in Islamabad. "The main bulk of our health work will continue."

Resich refused to comment on whether the difficulties were related to Pakistani authorities denying aid workers access to areas or whether it is was due to fears over security of staff.

He said three offices in northwestern Khyber Pakhtunkhwa province were being shut down, as well as three in Lahore, Muzaffarabad and Jacobabad. Offices in Islamabad, Quetta, Karachi and Peshawar will continue to function.

The ICRC's main projects in Pakistan focus on the treatment of civilians wounded in fighting between government forces and militants, mainly in Khyber Pakhtunkhwa as well as Baluchistan.

Most civilians affected by the closure of Red Cross offices are people displaced by violence or floods, who were receiving basic aid from the ICRC, said Resich. Some of these communities, he said, were no longer "critical."

Elsewhere, the Pakistani Taliban said on Thursday they had killed 15 soldiers kidnapped last month in revenge for military operations against them.

Officials confirmed that 15 bodies, with signs of torture and gunshot wounds, had been found in the Thal area of the northwestern Hangu district, near the unruly northwestern tribal areas along the porous border with Afghanistan.

• A Permanent Economic Emergency