KYIV, Ukraine (AP) — Wildfires in eastern Ukraine have killed at least five people and detonated unexploded ordnance fired during fighting with Russia-backed separatists, authorities said Thursday.

About 2,200 hectares (5,500 acres) were on fire in the Luhansk region, the state forestry agency said.

In the town of Stanichna Luhanska, flames engulfed houses on two streets, on one of which shells remained from fighting in 2014-16, the local administration said on Facebook. Stanichna Luhanska is just outside the rebel-controlled city of Luhansk.

The Ukrainian Interior Ministry said at least five people have died in the fires, without providing details.

Ukrainian President Volodymyr Zelenskiy said in a statement that some of the blazes may have been set off by artillery fire from the rebel-held territory.

Heavy fighting between separatist rebels and Ukrainian forces broke out in eastern Ukraine in 2014. Although the fighting has died down significantly, sporadic clashes are still reported.