ANKARA, July 7 (Xinhua) -- The number of Turkish soldiers killed by methane gas exposure during a cave operation in northern Iraq has risen to 12, the Turkish Defense Ministry announced Monday.

The incident occurred on Sunday during a search and clearance mission in Türkiye's Operation Claw-Lock zone, where Turkish forces were inspecting a cave formerly used by the Kurdistan Workers' Party (PKK). The operation aimed to recover the remains of a first lieutenant killed in 2022.

The colorless, odorless and flammable methane can lead to suffocation if present in high enough amounts.

Initially, 19 soldiers were hospitalized due to methane gas exposure, with five deaths confirmed on Sunday. The ministry later reported that three more soldiers died on Monday morning, bringing the death toll to eight. Subsequently, it was confirmed that four additional soldiers died in the hospital, increasing the total number of casualties to 12.

Türkiye launched Operation Claw-Lock in 2022 to dismantle PKK hideouts in northern Iraq's Metina, Zap, and Avasin-Basyan regions near the Turkish border.

The PKK is designated as a terrorist organization by Türkiye and has been engaged in an armed insurgency against the Turkish state for over four decades. The group announced its decision to disband and end its armed campaign in May. Enditem