Aug. 12 (UPI) -- The failed missile test that killed five scientists in Russia on Thursday had a nuclear propulsion system that used radioactive materials.
The small-scale nuclear reactor exploded at an offshore platform in the Arkhangelsk region near the Arctic Circle. Russian officials initially said the missile had a liquid-fired propulsion system but scientific director Vyacheslav Soloviev later confirmed it was nuclear-powered.
Three others were injured in the blast. All worked for the nuclear corporation Rosatom.
The scientists who died will be buried Monday. They were the "elite of the Russian Federal Nuclear Center," director Valentin Kostyukov said.
Russian media speculated that it could be the SSC-X-9 Skyfall, a nuclear-powered cruise missile. Russian President Vladimir Putin introduced the weapon during his state-of-the nation address last year.
The accident caused a radiation spike in the port city of Severodvinsk, Russia. Norway has stepped up radiation monitoring in the wake of the accident but hasn't found anything abnormal. American intelligence officials want to know about the mysterious explosion.