• As 200 prisoners now at large after Indonesian mass jailbreak

Another U.S. citizen has been detained in North Korea, officials said Sunday.

Kim Hak Song, who was working at Pyongyang Science and Technology University, was held for “hostile acts against the republic,” the state-run news service KCNA said.

Pyongyang University of Science and Technology, where Kim had been working, confirmed that he was detained Saturday as he was preparing to leave the country. It said Kim was doing agricultural development work not connected with the university.

Kim is the fourth U.S. citizen to be held by the isolated country amid diplomatic tensions.

A third U.S. citizen, Kim Sang Dok, was detained in late April on similar grounds.

In the meantime, Indonesian authorities have said about 200 inmates remain at large two days after a mass escape from an overcrowded prison on Sumatra island.

The breakout at Sialang Bungkuk prison in Pekanbaru on Friday occurred when prisoners were let out of their cells to perform prayers. They broke through a prison door, overwhelming the few guards on duty.

Police said 242 men had been recaptured by Sunday morning, leaving about 200 still at large.

Authorities were initially uncertain how many prisoners had escaped, estimating the numbers at between 100 and 300.

Police said some of the men surrendered or were returned by their families and others were captured by local residents, police and soldiers.

Various officials have said the prisoners were angry about poor conditions and treatment. The prison has a capacity of about 360 but was holding more than 1,870 men, according to a local police spokesman, Guntur Aryo Tejo.

Tejo said four of the escaped inmates were apprehended by police late on Friday about 60 miles from the prison, on a bus heading for West Sumatra province.

Hundreds of police and soldiers have been deployed in the hunt for the prisoners.

Jailbreaks are common in Indonesia, where overcrowding has become a significant problem in prisons that are struggling to cope with poor funding and an influx of people arrested under a “war on drugs”.

Friday’s escape was the biggest since July 2013 when about 240 prisoners, including several convicted terrorists, escaped after a deadly riot at a prison in Medan, the capital of North Sumatra province.

NBC with additional report from Guardian