Russia’s Investigative Committee said on Wednesday that a freight train derailment in Russia’s southwestern Belgorod region was due to a “terrorist act” and announced it was opening a criminal investigation into the incident.

A locomotive and 11 empty wagons of a freight train derailed shortly before midnight in the Novooskolsky district of the Belgorod region, near the border with Ukraine, Belgorod Governor Vyacheslav Gladkov said on Wednesday morning, citing unspecified “illegal interference” as the cause of the incident.

Gladkov added that there had been no casualties and that passenger trains passing through the area had been rerouted.

Baza, a Telegram news channel which is believed to have links to Russian security services, claimed that the train came off the rails after it hit an explosive device planted under the track, though Novaya Europe has been unable to verify these reports.

The incident is the most recent of a spate of fires and derailments on Russia’s railways in recent months, which Russian officials have blamed on Ukrainian forces or pro-Ukrainian saboteurs. Kyiv has not yet commented on Wednesday’s train derailment, however.