A new high tech battle tank hailed by Russia as a "masterpiece" appeared to break down on Red Square on Thursday during a rehearsal for the military parade at which it will make its long-awaited debut.
The tank's driver raised a small red flag to show he had problems but managed to drive on about 30 minutes later after an attempt to tow it away was abandoned, a Reuters witness said.
The parade announcer later announced that the stoppage had been planned to demonstrate how military equipment could be evacuated from the battlefield, prompting laughter from the rehearsal audience.
It was an inauspicious start for the Armata T-14 which will roll across the square in front of President Vladimir Putin and foreign leaders as part of Saturday's parade, marking the 70th anniversary of the end of World War II in Europe.
The tanks boast high-tech developments including automated loading, newly-developed armor and a remote-controlled gun turret operated by a three-man crew from a separate compartment at the front of the vehicle.
Part of a new generation of armored vehicles, the T-14 will not enter military service until 2020 and only a handful will appear at Saturday's parade. It is still in development and has yet to enter mass production.
But it will be the first new main battle tank deployed by Russia in 40 years, part of plans to produce 2,300 new tanks in the next five years under a costly rearmament program to replace ageing Soviet-era military vehicles.
"If we take the word of the Armata's designers and producers, this is a tremendous, unbelievable breakthrough in tank equipment," said Alexander Golts, defence columnist and deputy editor of online newspaper Yezhednevny Zhurnal.
Igor Korotchenko, a member of the Defense Ministry's advisory Public Council, was quoted by RIA news agency as saying the tank was a "masterpiece of modern tank construction," unlike any other tank in the world.
It has a lot to live up to, and some doubters.
Despite the Armata's technological advances, Moscow-based defense analyst Ruslan Pukhov said claims by the Russian media that the tank is more than a match for its long-serving American and German-built competitors could be overblown.
"It is also very important who will operate this tank," said Pukhov, director of the Centre for Analysis of Strategies and Technologies. "If it is to be one-year conscripts, I doubt that even such a fantastic machine could be a deadly weapon."
Another problem could be the cost. Russia plans to spend more than 20 trillion rubles by 2020 on modernizing its armed forces.
At an estimated cost of 400 million rubles per tank, the Armata T-14's price tag could set back production, Golts said. Russia's economy is in crisis, hit by a fall in global oil prices and Western economic sanctions over the Ukraine crisis.
"At 400 million rubles it is more expensive than a normal fighter jet," he said. "It looks as if this tank is made of gold."