Russian nuclear engineers killed by rocket explosion buried

Thousands of people have attended the burial of five Russian nuclear engineers killed by an explosion during tests of a new rocket.

The engineers, who died on Thursday, were laid to rest Monday in the city of Sarov that hosts Russia's main nuclear weapons research center.

The Defense Ministry initially said the explosion at the navy's testing range in Nyonoksa in the northwestern Arkhangelsk region killed two people and injured a further six, but the state-controlled Rosatom nuclear concern acknowledged later that the blast also killed five of its workers and injured three others.

Rosatom said the explosion occurred while the engineers were testing "a nuclear isotope power source" for a rocket.

Local authorities in nearby Severodvinsk reported a brief spike in radiation levels after the explosion.