A humanitarian organisation says at least 23 migrants have drowned off the coast of Tunisia as they attempted to cross the Mediterranean from Libya to Italy.

The Tunisian Red Crescent, speaking to Reuters news agency, said 70 other passengers from the overcrowded boat were rescued, as were a further 39 migrants on a second boat that sank in waters near the Tunisian port of Sfax.

The tragedy is the latest in a series of drowning incidents in the area.

The numbers attempting the dangerous crossing from African countries to Europe have increased as the weather has improved.