The embarrassing incident came moments before Putin delivered a major address on nuclear arms at this secret rocket launch site and just one day after another mishap prevented the Russian navy from test-firing two intercontinental ballistic missiles, known as ICBMs.

The mishaps blighted the largest war games staged by Russia in 20 years, which were meant to convince the United States that its missiles could penetrate any defense shield now being developed by Washington.

Russia's Northern Fleet said the missile blew itself apart 98 seconds after being launched from the Barents Sea by an underwater nuclear submarine.

It was supposed to hit a target on the Kamchatka peninsula in the far eastern corner of Russia but quickly strayed off course. The navy said it has launched an investigation but gave no immediate explanation for the accident.

The incident involved an RSM-53 missile, given the NATO specification SS-N-23, which was first developed by the Soviet Union in 1979.

A military source told Interfax the missile -- which is capable of delivering a nuclear strike on the United States -- probably went off course because its guidance system malfunctioned.

"It could have happened because the rocket was sitting in storage for too long," the military source said.

The war games came ahead of the March 14 presidential election in which Putin -- who has made army reforms one of his top priorities and relies heavily on support of Russian patriotic forces -- is expected to easily win re-election for a second term.

The explosion went off moments before Putin argued in a keynote address that Russia's nuclear arsenal would keep the country safe for generations to come.

He did not refer to the incident.

"I can inform to you with satisfaction that the tests conducted during these exercises were successful," Putin declared.

"Russia's strategic missile defense systems will in the near future be upgraded with the most modern equipment. Russia will guarantee its strategic security for the extended future."

But Putin did mention that there were "pluses and minuses during these exercises."

The explosion was not covered on the two state-controlled national television channels, the exact same procedure given to Tuesday's Barents Sea mishap.

The Kommersant business daily said Tuesday's launch went wrong when the first of two ICBMs failed to completely leave its launching pad. The second launch was then called off as a security precaution.

Navy commander Vladimir Kuroyedov told Interfax in response to the Kommersant report that he refused "to comment on gossip."

Western governments have openly accused Russian media of bias and helping pro-Putin parties gain control of parliament in December elections.

Instead the government-run channels trumpeted the fact that another ICBM was successfully launched by the Russian military from the Baikonur launch pad it is renting from its neighbor Kazakhstan.

Putin praised that launch as a sign that Russia could break through any missile shield that is under construction by the United States.

ITAR-TASS quoted Putin as saying that the SS-19 missile launched at Baikonur "has no competition" when it comes to breaking through potential defense mechanisms.

"We are talking about a very dangerous weapon with serious potential," Putin said.

WAR.WIRE