MOSCOW (AP) — Separatist officials in rebel-held eastern Ukraine say a methane blast at a coal mine has killed at least four people and 13 others are believed to be missing.

The Luhansk Information Center on Friday quoted emergency responders as saying that four bodies have been recovered from the mine in the village of Yurivka, west of the regional capital Luhansk.

Parts of the Luhansk region where the blast happened are under the control of Russia-backed separatist rebels who have been fighting Ukrainian government troops since 2014. The mine was closed because of hostilities in 2014 and reopened only last year.