CAIRO (Reuters) - The Egypt-led committee investigating the crash of a Russian passenger airplane in the Sinai peninsula last October said on Thursday it was referring the case to Egypt's attorney general, the first indication it suspects foul play.

After receiving a report on the crash from Russia suggesting suspected criminal activity, the committee decided to refer the case to the attorney general, it said in a statement.

Russia and Western countries have long said that they believe the flight was brought down by a bomb smuggled on board.

The investigation committee has said it had yet to find evidence of foul play, but Egypt's president said in a speech in February that the plane was downed by terrorists seeking to damage its tourism industry and ties with Moscow.

The Islamic State militant group, whose Egypt affiliate is waging an insurgency in the Sinai, said it smuggled the explosive aboard inside a soft drink can.

An EgyptAir mechanic whose cousin joined Islamic State in Syria is suspected of planting the bomb, sources familiar with the matter told Reuters in January.

The crash has called into question Egypt's campaign to eradicate Islamist militancy and damaged its tourism industry, a cornerstone of the economy.

(Reporting by Eric Knecht; Editing by Michael Georgy and Gareth Jones)