At least five persons, employees at Rosatom, Russia's nuclear energy company, were killed in an explosion at a military test site in northern Russia, the state-run firm said on Saturday.
According to CNN, the incident had taken place on Thursday near Severodvinsk, a town located in the Arkhangelsk region which is home to a naval base and a shipyard. Initially, two people were killed and four others were injured in the blast, the Russian Defence Ministry had said.
In a statement, Rosatom said that the five workers died "while testing a liquid jet propulsion system" and three more employees were wounded and "have burns of varying severity."
Local authorities said that sensors "recorded a short-term increase in the radiation background" at 11:50 am (local time) on Thursday when the blast took place. However, the radiation level started decreasing by 12:30 pm and returned to normal levels at around 2 pm, Rosatom said.
This was the second accident to hit the Russian military in less than a week. At least 12 people had suffered injuries in an explosion at an ammunition depot in the Krasnoyarsk region on Tuesday.