Seven people have died after a massive fire broke out at a major Russian defense research institute in Tver northwest of Moscow, according to reports.

Local authorities said 25 people were also injured in Thursday’s fire. TASS news agency reportedciting emergency services, and that at least 10 people are missing.

The death toll was initially estimated at five, but TASS said it had risen to seven.

“We confirm that there have been seven deaths at the moment,” TASS quoted the source as saying. She added that the number of casualties may rise.

The fire broke out in the administrative building of the Central Research Institute of the Air Defense Forces, which operates under the supervision of the Russian Ministry of Defense. It quickly engulfed the top three floors of the building, forcing those inside to leap out of the windows and causing the roof to collapse.

Pictures of the main building showed that it was completely consumed by fire. Video footage from the scene, about 160 kilometers (100 miles) northwest of Moscow, showed thick smoke and flames billowing from the institute’s windows.

The accident was followed hours later by unconfirmed reports of a fire at one of the largest chemical plants in Russia.

Pictures on social media allegedly show a large fire at the Dmitrievsky chemical plant in Kinsima, 400 kilometers (250 miles) northeast of Moscow.

They showed smoke rising from the self-described facility On her website As the largest producer of butyl acetate and industrial solvents in Russia and Eastern Europe.

No official cause was given for any of the fires.

Initial reports said that regional military prosecutors are investigating the cause of the fire in Tver. State news agency TASS said preliminary findings point to wire aging as a contributing factor.

The Defense Institute is involved in space research, including a unified air defense system for the CIS bloc of the former Soviet republics, according to the Russian Defense Ministry’s website.