The Greek Coast Guard has launched a major rescue operation to save 302 migrants after their boat capsized off the Mediterranean Island of Crete on 3 June. The coast guard reported that it had pulled three bodies from the sea after the boat sank.

The boat was spotted 75 nautical miles south of Crete in international waters, the Greek local press reported. Four nearby ships were participating in the rescue operation, with a further two patrol boats and two helicopters reported to be on their way to the scene.

AFP reported that boats crossing in the nearby area had thrown lifebuoys to the migrants as they struggled to stay afloat.

"The number of people in distress could be counted in the hundreds," a spokeswoman for the coastguard said. "People are in the water, boats crossing the area have thrown lifebuoys and are moving to save the migrants."

It was not immediately clear where the migrant boat had cast off from. However, the discovery of the boat south of Crete would appear to indicate that it set-off from North Africa.

A deal between Ankara and Brussels to manage migrant flows along the so-called 'Balkan route,' the short passage from Turkey to Greece, has seen migrants risking the far more perilous crossing from North Africa to the continent.

The humanitarian group Amnesty International has attacked the policy currently being pursued by the EU to return illegal immigrants arriving in Greece to nearby Turkey. The group has called the deal between Brussels and Ankara "illegal" and "reckless".

John Dalhuisen, Amnesty's director for Europe and Central Asia, said in a statement: "In its relentless efforts to prevent irregular arrivals to Europe, the EU has wilfully misrepresented what is actually happening on the ground in Turkey.

"It is to be expected that a new asylum system, in a country hosting the largest number of refugees in the world, would struggle. While there is value in supporting and encouraging Turkey to develop a fully functioning asylum system, the EU cannot act as if it already exists."

More than 1,000 migrants have drowned in the Mediterranean over the past week after a series of incidents involving crowded unseaworthy boats attempting to reach Italy from Libya, monitors said.

Sixty-two people were confirmed dead and some 971 were missing at sea and presumed dead in shipwrecks registered since 23 May, the International Organization for Migration (IOM) said, describing the period as "one of the deadliest" since the migration crisis began four years ago.

A Greek Coast Guard officer
A Greek Coast Guard officer (R) talks to refugees and migrants sitting on the deck of the Ayios Efstratios Coast Guard vessel following a rescue operation at open sea between the Turkish coast and the Greek island of LesbosReuters