<span style="color: #222222;">Russia's nuclear agency on Saturday said an explosion during missile testing in the Arctic left five of its staff dead. </span><br />'' <br />'' <span style="color: #222222;">Rosatom said the force of explosion on Thursday threw several of its staff from a testing platform into the sea. </span><br />'' <br />'' <span style="color: #222222;">The military had not initially said that the accident involved nuclear equipment, but said that radiation levels were normal afterwards.Nevertheless, officials in the nearby city of Severodvinsk reported that radiation levels briefly increased after the accident.</span><br />'' <span style="color: #222222;"><br />'' The Defence Ministry said in a brief statement that the incident occurred in the far northern Arkhangelsk region during testing of a liquid propellant jet engine when an explosion sparked a fire.<br />''<br />''Russian state news agencies quoted a defence ministry source as saying both Defence Ministry and Rosatom employees were killed. Rosatom said its staff were providing engineering and technical support for the "isotope power source" of a missile being tested.</span>