How many hijackers are involved in the news item?

Russian commandos have stormed a hijacked bus in the southern Tajikistan Republic and freed all 18 hostages aboard.(23)Security officials say the two gunmen who had held the bus for 8 hours were arrested. Officials say no one was seriously hurt in the take-over by a newly-created anti-terrorist squad. The gunmen seized the bus Wednesday night.(24)They had demanded more than a million dollars’ ransom and a helicopter to escape. Their motives are unclear although they reportedly told police they needed the money to help drug-addicted friends.