Malaysian police are hunting down an estimated 109 escaped asylum seekers who are believed to have burned down a detention centre on Monday.
Police are using road blocks and tracker dogs, and one report said 58 people had been arrested so far.
Officials admitted that the Lenggeng immigration centre in Negeri Sembilan state had long been over-crowded.
The detainees include asylum seekers and illegal immigrants from Burma, Bangladesh, Nepal, Iran and Nigeria.
"The manhunt is continuing. I urge the remaining escapees to surrender," district police chief Saiful Azly told AFP.
"Investigations showed that they were dissatisfied over cramped living conditions, the food and long detention periods," the state deputy police chief, Abdul Manan Mohamad Hassan, was quoted as saying by the official Bernama news agency.
He added that many had lost patience over the long process needed to resettle in third countries.
The centre houses a total of 540 migrants, many of whom had been there for more than a year.
Malaysia has been criticised in the past for its handling of the many people coming to the country in search of work or a safe haven from political persecution.
Its location makes it a magnet for tens of thousands of Asian migrants every year, many of whom find work, albeit illegally, in Malaysian homes and businesses.