Massive wildfires raging in Russia’s Ryazan Region may have been caused by an arsonist bent on sabotage, a Russian minister told media on Thursday.

“We see certain elements of sabotage. There are elements of arson at the root of the wildfires,” Emergencies Minister Aleksandr Kurenkov has said, as he updated the public on the situation. Russian law enforcement will investigate whether foul play was actually involved, the official added.

Ryazan Region, which is located some 150 kilometers southeast of Moscow, has been hit by some of the worst wildfires experienced in recent years. The ministry reported this week that flames had engulfed almost 15,000 hectares (37,000 acres) of forests.

The first blaze in the region was detected on August 7. In ten days, the wildfires had spread so much that the smoke from them could be smelled in the capital. Firefighters tackling the disaster are also dealing with hot weather and fast winds, which make their job more difficult, the minister explained.

“At the moment I assess the situation as difficult, but it is fully under control,” Kurenkov told journalists.

Russian law enforcement is currently on an alert for possible saboteurs seeking to damage the country on behalf of Ukraine. On Thursday, the domestic security agency FSB reported apprehending a Russian citizen who’d allegedly plotted “terrorist attacks” in the Russian exclave of Kaliningrad.

The suspect was described as a local resident and a supporter of Azov, a Ukrainian National Guard unit, whose members have a record of supporting far-right ideology. Moscow considers it to be an international terrorist organization. The FSB claimed that the man wanted to attack targets belonging to Russia’s Baltic Fleet and Khrabrovo Airport, which is used by both civilian and military aircraft.