The improvised bomb was placed close to a unit of border guards near Uludere town, Sirnak province, close to the Iraqi frontier, and triggered by one of the soldiers, the official, speaking on condition of anonymity, said.

The outlawed Kurdistan Workers' Party (PKK) often employs remote-controlled mines and home-made explosives against security forces in its deadly campaign for self-rule in Turkey's Kurdish-populated southeast.

The group, whose militants take refuge in mountainous bases in neighbouring northern Iraq, has recently stepped up attacks inside Turkey.

Some 45,000 people have been killed in the conflict since 1984 when the PKK, listed as a terrorist organisation by Turkey and much of the international community, took up arms against Ankara.