MOSCOW, Oct 17 (Reuters) - Russian President Vladimir Putin said on Wednesday that investigators were trying to work out the motive for a fatal attack on a college in the Crimean city of Kerch.

Putin made the comments at a joint news conference in Moscow with his Egyptian counterpart Abdel Fattah al-Sisi.

Eighteen people were killed and dozens injured at the college in Crimea on Wednesday when at least one attacker set off a bomb in the cafeteria and went through the building shooting at random, officials said. (Reporting by Andrew Osborn Editing by Tom Balmforth)