An unmanned Russian spaceship with tonnes of cargo for the International Space Station crashed into Siberia shortly after blast-off Wednesday in the latest blow to the country's embattled space programme.
The unprecedented accident raised concerns over the reserves of the six crew members on board the station and clouded the future of an ISS programme that relies almost exclusively on Russia following the retirement of US shuttles.
Both Russian officials and NASA said the ISS team -- which besides three Russians includes two US astronauts and a spaceman from Japan -- had at least two months of supplies and would not require an emergency evacuation.
But the disaster came especially hard for a Russian space programme that has suffered five previous launch failures in the past nine months and lost its most advanced commercial satellite shortly after blast-off last week.
"Attention, we have a contingency situation on board the rocket module," a flight control official reported 325 seconds (just over five minutes) into the mission in comments re-aired on state television.
"The mission is over," the announcer said as stunned scientists stared at their computer screens.
Local officials said fragments of the craft crashed into Russia's Siberian region of Altai on the border with Mongolia and China -- a remote region covered by soaring mountains and poorly accessible by road.
"The explosion was so powerful that it shattered windows nearly 100 kilometres (60 miles) away," said the region's Choya district head Alexander Borisov.
"I have lived here for 40 years and we have grown used to pieces (of detached carrier rockets) falling to the ground. But there has never been anything quite so powerful," he told RIA Novosti news agency.
Russia's Roskosmos space agency said in a terse two-sentence statement that the problem appeared to have developed in the propulsion system that led to a subsequent system shutdown.
But NASA officials said the mishap may have occurred because the Progress had problems detaching itself from its Soyuz-U carrier rocket.
State television said this was the first problem with a Russian or Soviet cargo delivery to space since 1978.
Both Russian and US space officials took immediate care to dispel suggestions that the accident may prompt an emergency evacuation of the ISS crew.
"Of course we have to study the situation, but provisionally we can say that it is not so critical that we should talk about the premature return of crew members from the ISS," mission control spokesman Vladimir Solovyov told Interfax.
"We have a very good backload of food, fuel and other consumables on board the ISS after the STS-135 shuttle mission," added NASA spokesman Kelly Humphries.
"It should not have an immediate impact on the crew."
The incident is of particular embarrassment to Russia after it celebrated the 50th anniversary this spring of the first manned flight of Yuri Gagarin -- the space pioneer who symbolised the Soviet Union's achievements during the Cold War.
Moscow suffered one its most embarrassing space failures in recent times in December when three navigation satellites for the new Russian Glonass system crashed into the ocean off Hawaii instead of reaching orbit.
Russia in February also lost a key military satellite and last week put into the wrong orbit a massive orbiter that was supposed to provide digital television and secure government communications for the eastern half of Russia.
Last week's failure reportedly prompted an angry Prime Minister Vladimir Putin to cancel a government meeting on space issues and demand a quick inquiry into what when wrong.
There was no comment from either Putin or the Kremlin on the cargo vessel disaster.
But the incident raised doubts about the future timetable for Russian missions: the next manned mission to the ISS is provisionally scheduled for September 22 and a cargo vessel is due to go up on October 28.
An industry source told RIA Novosti the crew may have to conserve both food and water because of the accident.
Another source said space officials had also informed captain Andrei Borisenko of the accident and that the team took the news calmly.
"The cosmonauts received this news with understanding," a Russian official told Interfax.
Explore further: Gully patterns document Martian climate cycles