MOSCOW, Aug 30: The two planes that crashed with the loss of 90 lives in Russia last week were both brought down by explosions in twin terrorist attacks, Russian officials said on Monday.

This was the first time the authorities confirmed both planes had been blown up, even though they had already said beforehand traces of a powerful explosive had been found in wreckage of both planes.

"Today we can say with the utmost certainty that both planes were destroyed as the result of terrorist acts," said security service spokesman Andrei Fetisov, quoted by the ITAR-TASS agency.

Fetisov added that investigators had concluded that the powerful explosive Hexogen was used in bringing one of the planes down. A spokesman for the FSB intelligence service said on Saturday that traces of Hexogen had also been discovered in the wreckage of the second plane.

One plane left Moscow bound for the Black Sea resort of Sochi with 46 people aboard. The other left the same Moscow airport headed for the southern city of Volgograd with 44 on board. All 90 people on both planes were killed. -AFP