Russian space agency chief Yuri Borisov says new intercontinental ballistic missile system is now in service, Russia’s news agencies report.

Yuri Borisov, the head of the Russian space agency Roscosmos, said Sarmat missiles have “assumed combat duty”, according to Russian news agency reports on Friday.

“The Sarmat strategic system has assumed combat alert posture,” the state-run TASS news agency quoted the Roscosmos chief as saying.

“Based on experts’ estimates, the RS-28 Sarmat is capable of delivering a MIRVed warhead weighing up to 10 tonnes to any location worldwide, both over the North and South Poles,” TASS said in its report.

White House National Security Council spokesman John Kirby said on Friday that he was not in a position to confirm reports that Russia had put the Sarmat on combat readiness.

Putin said in February that the Sarmat – one of several advanced weapons in Russia’s arsenal – would be ready for deployment soon.

In 2022, some two months after Russian troops invaded Ukraine, Putin said the Sarmat would “reliably ensure the security of Russia from external threats and make those, who in the heat of aggressive rhetoric try to threaten our country, think twice”.

The Sarmat is an underground silo-based missile that Russian officials say can carry up to 15 nuclear warheads, though the United States military estimates its capacity to be 10 warheads.

Known to NATO military allies by the codename “Satan”, the missile reportedly has a short initial launch phase, which gives little time for surveillance systems to track its takeoff.

Weighing more than 200 tonnes, the Sarmat has a range of some 18,000km (11,000 miles) and was developed to replace Russia’s older generation of intercontinental ballistic missiles (ICMBs) that dated from the 1980s.

Russia test-fired the Sarmat missile in April 2022 in the Plesetsk region of the country, located some 800km (almost 500 miles) north of Moscow, and the launched missiles hit targets on the Kamchatka peninsula, in Russia’s far east region.