The defence ministry late Thursday confirmed that the Bulava had exploded less than 30 seconds after launch from a submarine off northern Russia, reportedly the sixth failure in 11 test launches.

"It is bad that the emergency occurred during the functioning of the first stage. We thought this had been fully worked out," a source in the goverment's defence industry commission told the Interfax news agency.

"The failed launch of the Bulava will of course be examined in detail. I think the situation with the missile is not hopeless. No test of a new missile goes ahead without such problems."

The defence ministry said the intercontinental missile self-destructed "due to a failure in the first stage" after its launch from the nuclear-powered submarine the Dmitry Donskoi in the White Sea.

Its first stage motor worked for only 28 seconds, a defence industry source told the ITAR-TASS news agency.

The Bulava, which can be equipped with up to 10 individually targeted nuclear warheads, has a maximum range of 8,000 kilometres (5,000 miles) and was first successfully tested in December 2005.

It is the sea-based version of the Topol-M, designed to be launched from Moscow's newest Borei class of submarines.

The last test on December 23 also ended in failure when the missile exploded in mid-air after launch.

The RIA Novosti news agency cited a Russian intelligence source as saying that it was not ruled out that the problems were the result of deliberate sabotage in the production chain.

"A defect could have come into into the missile due to ineffective quality control on the side of the producer factory," the unnamed source said.

But the source did not rule out "that the defect could have come into the production chain as a result of criminal negligence, which also could be seen as sabotage."

The Kommersant newspaper said that 40 percent of the defence ministry's purchasing budget is currently being spent on the development of the Bulava.

It described the Bulava as the most "ambitious and long-standing" project in Russia's drive to modernize its weaponry after the fall of the Soviet Union.

"Its creation itself is meant to show that the country is still at a world-class level in weapons production," the newspaper said.