Indonesian police are searching for four foreign inmates who escaped prison on Bali by crawling through a narrow tunnel dug under the walls, the authorities said.
Prison officers became aware of the escape while conducting a morning check of inmates at the Kerobokan penitentiary in Denpasar, said Putu Ika Prabawa, an officer at Kuta Utara police station.
Prabawa said the four men were believed to have escaped through a 50cm by 70cm (20 inch by 28 inch) hole in a wall that connects to a tunnel leading to a main road.
He identified the four as Shaun Edward Davidson, 33, of Australia; Dimitar Nikolov Iliev, 43, of Bulgaria; Sayed Mohammed Said, 31, of India and Tee Koko King bin Tee Kim Sai, 50, of Malaysia.
Davidson is serving a one-year sentence for an immigration offence, while Iliev is serving a seven-year sentence for money laundering and another offence. Said and King are serving 14 and seven years respectively for drug offences.
Prabawa said police had distributed pictures of the escaped inmates to police stations across Bali.
"The tunnel is about 12 metres long and we suspect it took more than a week to build," the head of Kerobokan prison, Tony Nainggolan said. He said police believed the men were still in Bali and not far from the prison.
The head of the prison said 10 guards were on duty on Sunday night when the escape is believed to have taken place.
Jailbreaks are common in Indonesia, where overcrowding has become a problem in prisons that are struggling to cope with poor funding and an influx of people arrested in the president Joko Widodoa's war on drugs. Most prisoners have been convicted on drug charges.
Kerobakan has capacity for 323 inmates, but currently houses 1,378, according to government data. Last week, dozens of inmates escaped from an overcrowded prison in western Indonesia after floods caused a wall to collapse.
Last month, more than 440 prisoners escaped from an overcrowded prison on Sumatra island when they were let out of their cells to take part in Friday Muslim prayers. In July 2013, about 240 prisoners, including several convicted terrorists, escaped during a deadly riot at a prison in Medan, the capital of North Sumatra province.