Human Rights Watch on Thursday reported fresh assaults by unidentified gunmen in the Aegean Sea endangering the lives of migrants trying to reach Europe.
The rights group said witnesses had described eight incidents in which assailants "intercepted and disabled the boats carrying asylum seekers and migrants from Turkey toward the Greek islands, most recently on October 7 and 9."
A 17-year-old Afghan called Ali said a speedboat with five men armed with handguns had rammed their rubber dinghy on October 9.
"At first when they approached, we thought they had come to help us," Ali told HRW.
"But by the way they acted, we realised they hadn’t come to help. They were so aggressive. They didn’t come on board our boat, but they took our boat’s engine and then sped away," he said.
The Afghan teen said the masked men attacked three other boats in quick succession before speeding off toward the Greek coast "They spoke a language we didn’t know, but it definitely was not Turkish, as we Afghans can understand a bit of Turkish," he said.
Similar allegations had been made by migrants and rights groups during the summer.
The latest attacks had occurred near the island of Lesvos, HRW said.
A Greek coastguard source said the claims were under investigation but despite a search for the alleged perpetrators on land and at sea, no evidence had been found.
The coastguard in August arrested three men on the island of Samos suspected of preying on migrants seeking to cross over from Turkey.
They were dressed like members of the Greek coastguard and wore hoods, the coastguard said.
At the time, several refugees from Syria and Iraq told AFP on the island of Kos that they had been attacked by masked gunmen at sea, with some claiming the assailants stole their fuel and even their motors.
Some accused the Greek coastguard of assaulting them.