The Federal Counterintelligence Service said Monday that it is investigating the possibility that the rebellious Chechen republic was involved in a bomb attack on a Moscow railroad bridge at the weekend.


"One of the versions of the investigation" is that the regime of President Dzhokhar Dudayev "is involved in this bomb attack," said Sergei Bogdanov, chief spokesman for the Moscow department of the service, the former KGB.


"Fifteen minutes before the explosion a cargo train was due to go over the bridge" late Friday night, Bogdanov said, noting that Dudayev constantly threatened Russia with terrorist acts over its support of opposition forces in Chechnya.


Andrei Kostromin, another service spokesman, said the explosion occurred on a bridge across the Yauza river in the north of Moscow at 11:40 P.M. on Friday.


The bridge itself was undamaged but three meters of railroad track were destroyed, Kostromin said, adding, "It was a very powerful explosion."


A top city police official who declined to be named said a man was found dead near the explosion site.


"We established that this man installed the explosive devices but probably was killed due to careless handling of them," the official said.