About 500 migrants are feared dead after their ship was rammed by another boat near Malta last week, a migration body said.
Two Palestinian survivors told the International Organisation for Migration (IOM) that the boat had been intentionally sunk by traffickers.
They said boat had left Damietta in Egypt earlier in early September.
News of the sinking near Malta emerged as another vessel carrying 250 people sank off the coast of Libya.
Over 200 people are feared to have drowned in that incident.
Thousands of migrants have drowned in recent years as they attempt to reach Europe from North Africa and the Middle East.
Many do so in unsafe and overcrowded vessels.
IOM spokeswoman Christiane Berthiaume said that the two survivors were rescued on Thursday, the day after their boat sank.
They said traffickers rammed the boat after an argument on board. The IOM said there were nine known survivors in total.
The boat had been carrying Syrians, Palestinians, Egyptians and Sudanese, they said. The passengers included women and children.
The passengers were reportedly told to move to a smaller, less safe boat.
When they refused, the traffickers sank the larger vessel, the eyewitnesses said.
The Maltese authorities have not yet commented on the incident.