One person was killed and six others were wounded in an explosion on a vessel being repaired at the Severnaya Verf (Northern Shipyard) shipyard in St. Petersburg, a source in law enforcement agencies said on Monday.

“According to preliminary data, a blast of combustible vapors occurred, six people were injured and one person died,” the source told TASS.

The shipyard has declined to comment on the report, saying only that checks were ongoing.

A regional department of the emergencies ministry earlier said one person was killed and three others were injured in the blast inside the ship  of Algerian Navy.

The Severnaya Verf shipyard produces, repairs and modernizes naval ships for the Russian and foreign Navy.

The warship was sold to Algeria even during the Soviet Union and now is being upgraded

In April 2015 in the frame of military-technical cooperation with Algeria JSC «Concern «Granit-Electron» manufactured and supplied to JSC «Severnaya verf» shipbuilding yard «Purga-1159TM» system intended for installation to «RaisKorfou» ship. «Purga-1159TM» torpedoes and bombs fire control system is an upgraded version of the article remarkable for highest service characteristics. It provides 533 calibres twin-tube torpedoes fire control and RBG-60 jet bombs fire control by RBU-6000 systems.