Russia touted Thursday a new hypersonic missile said to hit speeds of more than 30,000 kilometres per hour, amid heightened tension with the US over arms control.
Russian President Vladimir Putin on Wednesday tracked final tests of a hypersonic missile dubbed "Avangard," which he says would defeat all existing missile defence systems.
When Putin unveiled the new weapon during his state of the nation address in March, he said the missile was highly manoeuvrable and flew at 20 times the speed of sound.
Senior officials now say the intercontinental projectile is considerably faster.
"During tests, Avangard reached the speed of Mach 27," or roughly 33,000 kilometres (20,500 miles) per hour, Deputy Prime Minister Yury Borisov said in televised remarks.
Mach 1 is a unit of measurement equivalent to the speed of sound.
"At this speed not a single intercepter missile can shoot it down," Borisov said.
He also claimed it was impossible to predict the missile's movements, which meant "missile defence is practically rendered obsolete."