The United Nations demanded urgent explanations from Thailand after reports emerged that its security forces shot dead up to 15 unarmed Rohingya refugees.

Officials from the UN refugee agency met with officials from the Thai Foreign Ministry in Bangkok, hoping to shed light on the February 22 incident near the island of Phuket on the Andaman coast, reports South China Morning Post.

UN High Commissioner for Refugees spokeswoman Vivian Tan said they were aware of earlier, vague media reports of shootings in Thailand from Rohingya boatpeople arriving in Sri Lanka and two recent refugee boats in Aceh, on the Indonesian island of Sumatra.

“We are aware of the reports but we don’t have our own information. We are trying to find out what happened,” Tan said.

“We … are watching this closely and we are concerned,” she added.

Thousands of Muslim Rohingya have fled across the border to Bangladesh or by boat to Thailand, Indonesia and Malaysia to escape from sectarian violence in Myanmar’s Rakhine state.

Thailand has publicly adopted a policy of “helping on” Rohingya boats intercepted at sea, supplying them with fuel, food and water, before towing them back out. Refugees aboard boats deemed unsafe will be taken to the Myanmar border, which proves to be problematic as Rohingyas are denied citizenship and would languish as stateless people.