A Russian RS-28 Sarmat intercontinental ballistic missile likely failed during a test earlier this month, according to arms experts and satellite imagery from the launch site.

Maxar satellite images from Sept. 21 show a crater about 60 meters (200 feet) wide at the launch silo at the Plesetsk Cosmodrome in northern Russia and damage around the area that was not visible in imagery from earlier in the month.

It was not clear from the imagery if the liquid-fueled Sarmat failed during a launch or if there was an accident during defuelling.

"By all indications, it was a failed test. It's a big hole in the ground," said Pavel Podvig, an analyst based in Geneva, who runs the Russian Nuclear Forces project.

"There was a serious incident with the missile and the silo."

Russia's defence ministry did not respond to a request for comment and has made no announcements about planned Sarmat tests in recent days.

The 35-meter RS-28 Sarmat, known as Satan II, has a range of 18,000 km (11,000 miles) and a launch weight of over 208 tonnes and can carry up to 16 multiple independently targetable re-entry vehicle nuclear warheads as well as some Avangard hypersonic glide vehicles, according to Russian media.