Russia says it has successfully test-launched a hypersonic missile, one of a range of nuclear-capable weapons announced by President Vladimir Putin earlier this month.
The country's defence ministry released video footage showing the missile detaching from a fighter jet and leaving a fiery trail behind it.
It said the intended target was hit.
On 1 March, Mr Putin described the Kinzhal missile - named after a type of dagger - as "an ideal weapon".
The Kinzhal is said to travel at 10 times the speed of sound and have a range of 2,000km (1,200 miles).
The defence ministry said the missile was launched from a MiG-31 jet that took off from an airfield in south-west Russia on Saturday.
"The launch went according to plan, the hypersonic missile hit its target," the ministry said.
Mr Putin is widely expected to be re-elected as Russia's president in a week's time.
As part of his annual state of the nation speech on 1 March, he played a video graphic that appeared to show missiles raining down on the US state of Florida.
The US state department said this was not "the behaviour of a responsible international player".