Philippine police say masked gunmen have helped three Chinese nationals, including two serving life sentences on drug charges, escape from jail guards who were driving them to court.

Regional police chief Benito Estipona says about 20 men armed with assault rifles and wearing ski masks blocked a vehicle carrying the Chinese to the trial court on Wednesday in Trece Martirez township in Cavite province south of Manila. The gunmen disarmed the guards and escaped with the three in a van that they later abandoned.

The three included a couple serving a life sentence for operating a clandestine methamphetamine labouratory in Manila. The couple are also co-defendants with the third escapee in a separate drug case.

National police chief Alan Purisima has ordered a nationwide manhunt for the escapees.