Two boats carrying more than 500 people are feared to have capsized off the coast of Myanmar in recent weeks, according to a joint statement released by two UN agencies on Thursday.

"According to preliminary information, the two vessels departed from Myanmar's Rakhine State in late June carrying mostly Rohingya passengers, reportedly including some who had travelled from refugee camps in Cox's Bazar, Bangladesh," the statement said, without specifying from where the reports emerged.

A first boat carrying 250 people lost contact shortly after heading out to sea. Another carrying 280 people is believed to have capsized off Myanmar's Ayeyarwady coast on July 8, according to the International Organization for Migration (IOM) and the ​UN Refugee Agency (UNHCR).

"If verified, this tragedy would add to the nearly 300 people reported to be missing or to have lost their lives in the Andaman Sea and Bay of Bengal so far this year, including Rohingya refugees and Bangladeshi nationals," the statement said.

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