A group of Sri Lankan hardline Buddhists protest outside the U.N. office in Colombo, Sri Lanka, Wednesday, Sept. 27, 2017. The protestors expressed their solidarity with Buddhists in Myanmar and opposed any move to bring Rohingya refugees to Sri Lanka. Placards in center reads "We do not want any Rohingya extremists who killed Buddhist monks." (AP Photo/Eranga Jayawardena)

COLOMBO, Sri Lanka - The U.N. refugee agency said Wednesday it was alarmed by a mob attack on Rohingya Muslim refugees in Sri Lanka, where government leaders called for stern legal action against perpetrators that included Buddhist monks.

On Tuesday, a group led by Buddhist monks stormed a United Nations-run safe house for Rohingya Muslims, claiming the residents were terrorists and demanding they be sent back to Myanmar, prompting police to relocate them. Dozens of protesters from Sri Lanka's majority Buddhist community led a mob that entered a multi-storied house at Mount Lavinia on the outskirts of the Sri Lankan capital.

In a statement, the United Nations High Commissioner for Refugees said it is "alarmed and concerned" by Tuesday's incident and urged the "public and all those concerned with refugees to continue extending protection and to show empathy for civilians fleeing persecution and violence."

Police took 31 Rohingya refugees, including 17 children, into custody Tuesday and moved them to a safe location.

A video clip posted by a nationalist group, Sinhala National Movement, on its Facebookpage shows protesters calling Rohingyas"terrorists who killed Buddhists in Myanmar" and saying that they can't live in Sri Lanka.

On Wednesday, finance and media minister Mangala Samaraweera condemned the attack, describing it as a "shameful act," and called for strong action against the perpetrators.

Health minister Rajitha Seneratne said he was depressed by the attack and urged law enforcement authorities to arrest the attackers.

Sri Lanka Buddhists make up 70 per cent of the island's 20 million people, while Muslims account for 10 per cent.

A half-million Rohingya Muslims have fled from Myanmar to Bangladesh in the past year, most of them since Aug. 25, when Rohingya insurgent attacks on security forces prompted a military crackdown and reprisals by majority Buddhists.

Rohingya have long faced persecution and discrimination in Buddhist-majority Myanmar, where the government denies them citizenship and considers them illegal immigrants. Extremist Buddhist monks in Sri Lanka have ties with their counterparts in Myanmar and monks in both countries have been accused of leading attacks on minority Muslims.

News from © The Associated Press, 2017