Terrorists in explosive vests have reportedly threatened Pakistan train passengers' lives if officials refuse to release imprisoned militants.

The separatist Baloch Liberation Army, which claimed responsibility for Tuesday's attack, released a statement saying its fighters had escaped with 214 hostages and since executed all of them, without giving any evidence to back that up.

Separatist militants fired at a passenger train in southwestern Pakistan on Tuesday, injuring a train driver, police and railway officials said.