Plant in Sergiev Posad previously made military equipment but officials downplay speculation blast was result of Ukrainian drone attack

• Russia-Ukraine war – latest news updates

An explosion has ripped through a factory said to house fireworks in the Moscow region, injuring at least 40 people and raising questions as to whether the blast was the result of an accident or of a targeted attack.

The explosion took place at about 10:40am local time on Wednesday at a factory workshop in Sergiev Posad, about 40 miles (65km) from central Moscow. Video of the blast showed a mushroom cloud of smoke rising into the air over the Zagorsk optical mechanical plant, which in the past has manufactured night-vision goggles and other imaging equipment for the Russian military. Factory officials ordered a “total evacuation” of the area.

Footage appears to show a strike on Olenegorsky Gornyak landing ship, which transports troops and military hardware

• Russia-Ukraine war – latest news updates

A Russian landing ship was struck and disabled in the country’s Black Sea port of Novorossiysk by an unmanned Ukrainian boat, known as a sea drone, Kyiv said, as onboard camera footage appeared to confirm the success of the night attack.

The 112-metre Olenegorsky Gornyak from Russia’s Northern Fleet, which has been used to transport troops and military hardware into occupied Ukrainian ports, was said to have been sufficiently damaged to have been put out of combat action.