A fire at a Russian military research institute inside the northwestern town of Tver killed two people on Thursday and injured dozens greater, countries’ news organizations pronounced.

Russian TV showed photographs of thick black smoke rising from inside the yellow four-storey building of the Central Research Institute of the Russian Air and Space Forces

Several of the institute’s employees had to jump out of windows on the upper floors to escape the flames, according to witnesses quoted by broadcasters.

“Two people were killed in the fire… Around 30 people were injured,” a source in the emergencies ministry said, TASS state news agency reported.

Several of the injured were taken to hospital, three of them requiring intensive care, said a spokesman for the Tver regional hospital, quoted by TASS.

Preliminary information suggests the fire was caused by faulty electric wiring, TASS added.

The defense ministry said that the institute focuses on research related to Russian air and space defense, in addition to the improvement of new anti-plane structures.

Accidental fires are unusual in Russia, wherein hundreds of blazes are recorded each year due to getting older and affected infrastructure and non-compliance with safety requirements which are regularly lax.