Zagorsk

Russian officials did not offer a suspected cause of the explosion at the Zagorsk plant in the region around Moscow, which added to jitters about potential Ukrainian drone strikes.

Investigators say pyrotechnic equipment was being stored in the rented warehouse on the grounds of the Zagorsk Optical and Mechanical Plant where the blast occurred.

Mr Vorobyov said the explosion occurred in a warehouse storing fireworks which was located on the grounds of the Zagorsk optics manufacturing plant.

Local officials said the epicenter of the blast was at a warehouse storing fireworks located on the grounds of the Zagorsk Optical-Mechanical Plant in the town of Sergiyev Posad, less than 50 miles from Moscow.

The atheist Soviet authorities closed Trinity Lavra in 1930 and renamed the town Zagorsk in honor of a Soviet revolutionary hero.