The soldiers were on patrol near the town of Baskale, Van province, some 40 kilometers (25 miles) from the Iranian border, when the landmine went off.

Separatist rebels from the Kurdistan Workers' Party (PKK) was suspected to be behind the explosion, said the source, speaking on condition of anonymity.

The blast comes a day after six soldiers were killed and three others wounded in two separate clashes with PKK rebels in the southeast.

The government is trying to win public support for a planned package of reforms to boost the rights of Turkey's Kurdish community and encourage the PKK to lay down arms.

The PKK, listed as a terrorist group by Ankara and much of the international community, has been fighting for self-rule in Turkey's mainly Kurdish southeast and east since 1984, in a conflict that has claimed some 45,000 lives.

Last week, the rebels announced that they were extending a unilateral ceasefire to the end of the Muslim holy month of Ramadan on September 22.

They warned, however, that they would defend themselves if they came under attack from the Turkish military.

Ankara has never recognised the PKK's unilateral truces and the military operations against the rebels have continued.