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 (30 miles) 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.

Meanwhile, two Albanian seamen who took part in the rescue operation for the Norman Atlantic ferry have died from injuries incurred in an accident, the Italian navy said Tuesday.

The merchant sailors were on board a tugboat when the cables attaching it to the stricken ferry snapped, the navy said without providing further details.

The deaths mean the number of lives lost as a result of Sunday’s fire on the ferry has risen to 12.

Nearly 40 passengers thought to have been on the boat remain unaccounted for but it is unclear whether that is due to inaccurate manifest lists or whether some of them may have perished unnoticed in the chaotic early stages of the disaster.