The claim, which could not be confirmed, was made by a group calling itself the Kurdistan Freedom Falcons (TAK) in a message to Firat, a pro-Kurdish news agency based in Europe.

The Turkish authorities have identified an electrical short circuit as the probable cause of the blaze.

"The sabotage is a response to the policies of massacre followed by the Turkish state towards the Kurds," the message said.

It added that its actions would continue "as long as the extermination policies of the Turkish state against the Kurds are in force."

The Turkish goverment says the TAK is an offshoot of the banned Kurdistan Workers' Party (PKK) regarded as a terrorist organisation by the United States and the European Union.

The PKK denies any links with the TAK, which has targeted the tourist industry and in one attack in July last year planted a bomb that killed a British woman and an Irishwoman.

The blaze started at around 3:30 p.m. (1230 GMT) in Terminal C where outgoing and incoming freight is stored, and the flames were brought under control about an hour later.

"The fire is now completely under control. Cooling-off work in is progress," Irfan Balta, the airport's chief of operations, told the NTV news channel.

Istanbul deputy governor Fikret Kasapoglu said it was not immediately clear what had caused the blaze, but said officials suspected it was triggered by either a short-circuit or goods catching fire from sparks of a welding machine.

Three people were hospitalised with smoke inhalation, and there was extensive damage in the cargo building, he added.

"Large parts of the building caved in. We are trying to prevent the fire from spreading to other cargo holds. But there is no danger at the moment," he told the Anatolia news agency.

He also added that flights were continuing normally.

An official from the state airport authority told AFP earlier that there were delays as some incoming planes were ordered to delay their landings and others were rerouted to the city's second airport on the Asian side of the Bosphorus Strait.

The site of the fire was located at a distance from the international and domestic flights terminal and airline company representatives said passengers were out of danger.

Dozens of firefighters, aided by two fire-fighting planes, were involved in battling the flames which sent flames and huge plumes of black smoke over the aiport.

Explosions could be heard as the blaze enveloped the goods kept in the cargo section, Anatolia said.

Ataturk Airport is the country's biggest airport and millions of foreign tourists pass through it each year to fly to Turkish resorts or destinations in the far east.