Libya's coastguard has rescued 84 illegal immigrants from Africa in the sea off Tripoli, Lana news agency quoted a maritime official as saying on Thursday.

"The Libyan coastguard supported by special forces of the Navy rescued 84 illegal migrants of various African nationalities whose boat had broken down in the sea north of Tripoli" late on Wednesday, the official said.

"All of the migrants are healthy and have been transferred to the (western) port of Zawiya where they were handed over to agencies that fight illegal immigration."

On Tuesday nearly 100 migrants from sub-Saharan Africa escaped from a detention centre at Gharyan in southwestern Libya. Seventy-five of them were subsequently arrested.

With a 1,770-kilometre (1,100 miles) coastline, Libya is a favoured country of transit for would-be migrants from southern and western Africa seeking to reach Europe in search of a better life.

But the journey is frequently perilous, and hundreds of Africans have drowned in the Mediterranean en route for Europe this month alone. Hundreds have also been rescued.