Four Turkish soldiers have been killed in two separate incidents in northern Iraq where they are battling Kurdish militants, the defence ministry said Monday.

Three soldiers died and two were injured when an improvised explosive device went off Sunday in an area where Turkish forces have been conducting an operation against fighters from the Kurdistan Workers’ Party (PKK), the ministry said.

Another soldier was killed and one wounded in a shootout with Kurdish fighters near a Turkish military base, it said.

Turkish forces routinely conduct operations against PKK bases in rugged mountains in northern Iraq.

The group is listed as a terrorist organisation by Turkey and its Western allies.

Turkish troops have maintained a network of bases in Iraq since the mid-1990s under security agreements struck with Saddam Hussein’s regime.

The PKK has waged a rebellion in the mainly Kurdish southeast of Turkey since 1984 that has claimed more than 40,000 lives.

The PKK’s pan-Kurdish agenda — for a homeland straddling parts of Syria, Turkey, Iraq and Iran — has often put it at odds with Iraq’s autonomous Kurdish government, which has sought to maintain good relations with Ankara.