Kabul - A group of unknown gunmen abducted a French aid worker Monday in the Afghan capital, Kabul, and shot dead an Afghan driver who tried to rescue him, police said.

The Frenchman was kidnapped as he was walking to his office with a colleague, said Zemarai Bashary, an interior ministry spokesman.

The two men, who were working with a nongovernmental organization in the country, were walking to their office in the Kart-e-Parwan neighbourhood when three gunmen snatched the Frenchman and took him to an unknown location by car, said a senior police official who requested anonymity.

"An Afghan driver for the intelligence service who tried to stop the abduction was killed by the kidnappers," the official said.

He said that as the Afghan driver scuffled with the abductors, the other aid worker escaped. The official said a search operation involving hundreds of police was being conducted in Kabul and all roads linking the city to neighbouring provinces had been closed by security forces.

The French foreign ministry confirmed the abduction on Monday, saying in a press statement that it was "mobilizing to obtain the liberation of our countryman as quickly as possible."

The ministry did not identify the kidnap victim, noting that "discretion is indispensable ... in the interest of our countryman's safety."

"The abductors were wearing a kind of uniform worn by Afghan security forces," Mohammad Karim, 23, a shopkeeper in the area, who saw the incident, said.

"The men pointed their guns at the bystanders and warned us not to get closer to them after they shot dead the Afghan driver," Karim said adding they immediately drove away in a red Toyota Corolla.

No group immediately took responsibility for the abduction. Alishah Ahmadi, Kabul's deputy police chief blamed criminal gangs for the abduction.

"I believe they were criminals who are doing this kind of abductions for ransom," he said, adding that the search operation would continue until the hostage is freed.

The kidnapping came amid mounting concerns among international aid workers in Kabul regarding their safety. Kabul, which houses thousands of international troops and has streets packed with thousands of Afghan police and army forces, has seen a spate of terrorist incidents recently.

An aid worker with South African and British citizenship working with an organization helping disabled people was shot dead as she was walking to work in the western part of Kabul late last month.

Days later, a Briton and a South African working with an international courier service were killed when their security guard opened fire on their vehicle in the centre of the city. The cause of the attack was not known, but Afghan police officials did not rule out terrorists being behind the attack.

A suicide bomber attacked the Ministry of Information and Culture Thursday, killing himself and five ministry workers. Two other militants who accompanied the bomber escaped after shooting guards at the ministry's front gate.

Armed criminal gangs, who are widely believed to have links to high level Afghan security officials, and who are taking advantage of insecurity caused by Taliban-led violence, have been behind a series of kidnappings of wealthy Afghans recently.

Among the most recent victims was Humayun Shah Asifi, the brother- in-law of Afghanistan's former king who died last year, was kidnapped by a group of criminals in Kabul city late last month. Asifi was freed in a operation by intelligence forces. The kidnappers had asked his relatives for 5 million dollars for his release. (dpa)