Dozens of Rohingya refugees are feared to have drowned after a wooden boat with an estimated 150 people on board capsized off the coast of Indonesia’s Aceh province.

The boat is thought to have run into trouble some 19km (12 miles) from the beach of Kuala Bubon on the west coast of Aceh after it hit rough seas on Wednesday morning.

Six people – four women and two men – were rescued from the boat by Acehnese fishermen and taken to a shelter, where they were able to speak to Faisal Rahman, a representative from the UN refugee agency (UNHCR).

Rahman said the survivors’ testimony suggested many had drowned.

“We can’t confirm the exact number of casualties, but according to information from the six who were rescued, there are many dead,” he told Al Jazeera. “They assume about 50 people died when the boat capsized.”

It is thought that most of those presumed to have died were women and children who were unable to swim, and carried out to sea by the currents.

Amateur footage shot by local fishermen at the scene, which has been widely shared on Indonesian social media, showed survivors standing on the upturned hull.

They all appeared to be male.

Emaciated and dressed in shorts, they waved at the fishermen and begged to be rescued.

Amiruddin, a fishing community leader in the Aceh Barat district where Kuala Bubon is located, said a search and rescue boat from Indonesia’s National Search and Rescue Agency had been dispatched on Wednesday.