ANKARA, Turkey (AP) — A gas leak inside a coal mine in northern Turkey killed eight workers Monday, Turkish officials said.

The miners were working on opening up space to reach a coal deposit when they were hit by a sudden methane gas discharge, Burhan Inan, the head of Turkey's coal mining authority, told Turkish state television TRT.

Eight workers died from breathing the gas or getting trapped under coal dust that blanketed the mine after the discharge. One worker was rescued with injuries, and six others were evacuated unharmed, Inan said.

The accident in Zonguldak province, on the Black Sea coast, comes at a time when Turkey is trying to improve safety conditions in its mines. The government has been shutting down dangerous mines or those operating without proper licenses.

Turkey's most deadly mine disaster occurred in 1992, when a gas explosion killed some 270 workers in Zonguldak.