The U.N. refugee agency has told Thailand it is profoundly concerned about the arrest of 32 refugees and asylum seekers during the last two weeks.

In a press release Monday, the U.N. High Commissioner for Refugees said asylum seekers should not be locked up simply for being refugees.

Those arrested in four locations included Pakistanis and Sri Lankans. Some were Ahmadiyah Muslims, who are persecuted in Pakistan for their beliefs.

The UNHCR said it would like to see Thailand end its practice of indefinite detention for some refugees.

Thailand, like many Asian countries, has no national asylum system. Any foreigner who enters the country without proper documentation is subject to arrest, prosecution, detention and deportation.

Earlier this month, Thailand released 96 Ahmadiyah Muslim refugees who had been held for six months. They are being housed in Bangkok until they are resettled to a third country.