The head of the Russian space agency said Friday that the Sarmat intercontinental ballistic missile, which Moscow claims can deploy 10 or more nuclear warheads and move at hypersonic speeds to outwit defenses, had been put "on combat duty,” according to state media outlet RIA Novosti.

Pavel Luzin, a Russian military analyst, said the announcement meant that the missile had been deployed in a silo and was ready to be used. That readiness, however, might be more "on paper” than in reality, he added, given the Sarmat’s limited amount of testing.

The space agency director, Yuri Borisov, did not give details of what he meant by "combat duty,” nor did he say how many of the missiles had been deployed or where.