Athens: A freighter with hundreds of migrants on board issued a distress signal on Tuesday while sailing northwest of the Greek island of Corfu, the Greek coastguard said.
A coastguard source said the Moldovan-flagged ship Blue Sky M had some 400 migrants on board and that a Greek navy frigate and a rescue helicopters had been dispatched to the area.
Greek media reported that a number of armed men are on board the vessel, but the coastguard has not confirmed this.
The freighter is suspected to have suffered engine failure.
Winds of around 49 kilometres an hour were blowing in the vicinity.
In the same area, the Greek ferry Norman Atlantic caught fire on Sunday with over 400 passengers and crew on board, prompting a major rescue operation by Italy and Greece.
Ten passengers have so far been confirmed dead and dozens are still unaccounted for from that incident.