A senior Russian government official has hinted his country may retaliate against Ukraine in response to an explosion in Moscow that claimed the lives of a top Russian general and the military man's assistant.

Former Russian President Dmitry Medvedev, who is currently the deputy chairman of Russia's Security Council, spoke on Tuesday about the explosion during a meeting of senior government officials.

Russia's investigative authorities say Lieutenant General Igor Kirillov and his assistant were killed in the blast early on Tuesday. They say an explosive device had been set up near the entrance to his home.

Medvedev told the meeting that investigators must find the killers in Russia.

He said everything must be done to destroy the person in Ukraine who ordered the explosion.

Russia's state-run Tass news agency has also quoted him as saying that Ukraine's leaders will pay a heavy price for Kirillov's death.

Ukraine's security services alleged in an announcement on Monday that Kirillov had committed war crimes. The Russian lieutenant general was the head of a military unit that is in charge of biological and chemical weapons.

Ukrainian media outlets are speculating that the explosion was carried out by Ukraine's security authorities.

Ukrainian presidential adviser Mykhailo Podolyak told NHK on Tuesday that Ukraine was not involved in the blast in Moscow. He added that his country acts within the laws.