The bomb was set off by remote control by Kurdish separatists as a military convoy passed by in Sirnak province, on the mountainous border with Iraq, the sources said.

The dead included two officers, they said.

In recent weeks, Turkey has strengthened its military presence on the Iraqi border, with no-go security zones and live ammunition manoeuvres seen as signs of a possible cross-border operation to neutralise the rebel Kurdistan Workers Party (PKK).

Iraq lodged an official complaint with Turkey on Saturday claiming it had bombarded Iraq's northern Kurdish region and warning that the attack against Kurdish rebels could destabilise the region.

Turkey says the PKK, whose 22-year insurgency in eastern and southeastern Turkey has claimed more than 37,000 lives so far, is acting under the protection of Iraqi Kurds allied to the United States.