NEW DELHI (Reuters) -- At least 180 ethnic Rohingya stranded at sea for weeks after leaving Bangladesh in November are feared dead, as their rickety boat is thought to have sunk this month, the United Nations refugee agency (UNHCR) said.

Citing unconfirmed reports, the agency said the “unseaworthy” boat probably sank after it went missing in the sea. Last week, two Myanmar Rohingya activist groups said up to 20 people died of hunger or thirst on a boat that was stranded at sea for two weeks off India’s coast. The boat with at least 100 people was said to be in Malaysian waters.