At least nine people died when an overcrowded migrant boat capsized off the coast of Libya and 144 more were rescued, the Italian coast guard said.

It follows another heavy weekend for maritime rescue services operating off North Africa.

A spokesman for the Italian coastguard said 5,629 people were rescued from 22 different vessels in the three days between 10 April and 12 April.

Vessels and aircraft from the Italian coast guard and navy were involved, along with merchant ships and an Icelandic patrol boat assigned to the European Triton border protection operation.

Rescue services were alerted yesterday afternoon about the boat that capsized some 80 miles north of the Libyan coast.

Nine bodies were recovered and were brought to shore on Italian coast guard and navy vessels.

Today, Tunisa's coastguard and navy rescued almost 180 African migrants from two boats that broke down as they headed from Libya to Italy, the Red Crescent and an AFP correspondent said.

The Red Crescent said the migrants, 94 on one boat and 84 on the other, sent out a distress call from off the coast of southeast Tunisia as they headed for the Italian island of Lampedusa.

A previous count had said 174 were rescued.

The 178 migrants from Africa were evacuated to the Tunisian port of Zarzis and provisionally lodged in a warehouse.

They were mostly from Somalia, Ghana, Gambia, Sudan and Niger, said Dr Riyadh Belhaj of the Zarzis Red Crescent that took them in, adding that all passengers on the two boats were rescued.

Around 3,500 people are estimated to have drowned and 170,000 reached Italy as the migrant crisis has intensified with continuing instability in Libya, the staging point for most of the boats trying to cross to Sicily.

The number of boats carrying migrants aiming to reach the European Union from Africa has picked up in recent weeks as fine spring weather has made the passage safer.

In February, more than 300 drowned when attempting the crossing in cold weather and rough seas.

At least 480 migrants died in the Mediterranean in the first three months of 2015, compared with fewer than 50 in the same period last year, the International Organisation for Migration said on Friday.

Around 3,500 are estimated to have drowned last year when more than 170,000 migrants managed to reach Italy by sea.