"We heard three explosions, but we don't know what caused them," said Turkish army spokesman in Silopi Murat Pekgulec. "The Turkish army is not involved," he added.

Turkey has had several thousand soldiers in Kurdish-controlled northern Iraq for several years, in a bid to stop separatist Kurdish rebels from sneaking across the border into Turkey, which witnessed a 15-year bloody Kurdish rebellion for a separate homeland.

Pekgulec added the blasts appeared to have happened on the Iraqi side of the border between Iraq, Turkey and Syria.

Other witnesses said they heard light arms fire at around the same time at 3:00 am (00OO GMT).

The explosions shook the walls of houses in Silopi, just 10 kilometres (six miles) from Iraq, but AFP journalists in the area said there was no sign of any extra activity in Silopi hospital or of any extra military checkpoints.

"We heard the explosions. I don't think they happened in our territory," said a policeman who asked to remain anonymous.

"At first I thought it was an earthquake, then there were several detonations, and I thought they were bombs", another policeman added.

The border region of northern Iraq, which has been controlled by the Kurds since the end of the 1991 Gulf War, has not seen any major clashes since the start of the US-led war on Iraq on March 20.

Beyond Silopi begins the military zone which is tightly controlled by the army, and off-limits to journalists.

SPACE.WIRE