A short-term spike in radiation levels has been recorded after a rocket engine exploded during a test in Russia, regional authorities said.

Moscow’s defence ministry said two were killed and four others wounded after the blast at a military shooting range in the northwestern region of Arkhangelsk.

The ministry said there was no release of radioactivity or any toxic substances.

However, Ksenia Yudina, a spokeswoman for the city of Severodvinsk, which has a population of around 185,000, said: “A short-term rise in background radiation was recorded at 12 o’clock in Severodvinsk.”

The defence ministry confirmed six servicemen and civilian engineers were injured, and two died of their injuries. It said the explosion took place during the test of a liquid-propellant rocket engine.

Huge explosion at Russia ammunition depot: In pictures Show all 12 1 /12 Huge explosion at Russia ammunition depot: In pictures Huge explosion at Russia ammunition depot: In pictures An explosion at an ammunition depot near the town of Achinsk in Russia on August 5 AFP/Getty Huge explosion at Russia ammunition depot: In pictures Fire and smoke rise from the site of an explosion at an ammunition depot in Russia on August 5 Reuters Huge explosion at Russia ammunition depot: In pictures People watch from afar as as fire and smoke rise from the site of an explosion at an ammuntion depot in Russia on August 5 Reuters Huge explosion at Russia ammunition depot: In pictures Flaming residue is scattered in an explosion at at an ammunition depot near the town of Achinsk in Russia on August 5 Reuters Huge explosion at Russia ammunition depot: In pictures An explosion at an ammunitions factory is seen from 10 miles away in the town of Achinsk, Russia on August 5 AP Huge explosion at Russia ammunition depot: In pictures Fire and smoke rise from the site of an explosion at an ammunition depot in Russia on August 5 Reuters Huge explosion at Russia ammunition depot: In pictures Smoke rises from the site of an explosion at an ammunition depot as the sun sets in the town of Achinsk, Russia on August 5 AFP/Getty Huge explosion at Russia ammunition depot: In pictures An explosion at an ammunitions factory is seen from 10 miles away in the town of Achinsk, Russia on August 5 AP Huge explosion at Russia ammunition depot: In pictures Smoke rises from the site of an explosion at an ammunition depot in Russia on August 5 AFP/Getty Huge explosion at Russia ammunition depot: In pictures Smoke rises from the site of an explosion at an ammunition depot in Russia on August 5 AFP/Getty Huge explosion at Russia ammunition depot: In pictures Smoke rises from the site of an explosion at an ammunition depot in Russia on August 5 AFP/Getty Huge explosion at Russia ammunition depot: In pictures Smoke rises from the site of an explosion at an ammunition depot in Russia on August 5 AFP/Getty

City officials said background radiation levels had fully “normalised”.

An Arkhangelsk port official said the Dvina Bay area of the White Sea would be closed off to shipping for a month following the explosion, the Interfax news agency reported.

The rocket engine explosion occurred at a weapons testing area near the village of Nyonoksa in the Arkhangelsk region, 800 miles north of Moscow, said the Interfax news agency.

Russian media said an area near Nyonoksa is used for tests on weapons including ballistic and cruise missiles used by the navy.

It came two days after 16,500 people were forced to flee their homes when massive blasts rocked an arms depot in Siberia.