The sinking of a migrant boat off the coast of Greece may be “the worst tragedy ever” in the Mediterranean sea, according to the EU Commissioner for Home Affairs Ylva Johansson.

“We don’t have all information yet on what has happened but it seems like this is the worst ever tragedy we’ve seen in the Mediterranean,” she told a press conference in Brussels on Friday, CNN reported.

The Greek coastguard said nine Egyptian nationals aged between 20 and 40 were also arrested on suspicion of setting up a criminal organization, manslaughter by negligence, exposure to danger, and causing a shipwreck, CNN said.

The BBC on June 18 said it “has obtained evidence casting doubt on the Greek coastguard’s account of the migrant shipwreck in which hundreds are feared to have died.“

Analysis of the movement of other ships in the area suggests the overcrowded fishing vessel was not moving for at least seven hours before it capsized, the BBC said.

“The coastguard still claims that during these hours the boat was on a course to Italy and not in need of rescue,” the BBC reported.