International charity ships and Libya's coastguard picked up several hundred migrants on Saturday as smugglers trying to take advantage of calm seas launched a flurry of boats towards Italy.

Libyan coastguard vessels intercepted three migrant boats, the first an inflatable dinghy that had broken down with 125 people on board off Zawiya, just west of the capital, Tripoli, said Ayoub Qassem, a coastguard spokesman.

The second boat was turned back off Garabulli, east of Tripoli, and had 112 people on board, while a third boat with 98 migrants on board was intercepted off Abu Kamash, near Libya's border with Tunisia.One boat with more than 100 migrants on board made it as far as the Aquarius rescue ship about 21 miles from the coast to the west of Tripoli. The ship was preparing to transfer the migrants to Italy.

Rescuers on board the Aquarius said the migrant boat was on the verge of completely sinking when it reached them. More than half the migrants on it were Nigerians, with the rest from other sub-Saharan African countries as well as two Palestinians."All but one of the five balloons holding the boat up were either completely deflated or deflating and there were still about 120 people inside the boat, so a very, very precarious condition," said one of the rescuers, Max Avis.

Recent years have seen thousands of migrants infiltrate the vast southern border of Libya in attempts to cross the Mediterranean to Europe. At least 337 migrants have died or disappeared off the coast of Libya since the start of the year, according to the International Organization for Migration (IOM).

Libya is the main departure point for migrants attempting to reach Europe by sea. More than 600,000 migrants have crossed the central Mediterranean to Italy over the past four years as people smugglers took advantage of a security vacuum in Libya. Thousands more perished at sea. Since last summer the rate of departures dropped sharply after smugglers in the Libyan town of Sabratha struck a deal with the Tripoli government to halt their activities and were then pushed from the town by rival armed groups. Libya's EU-backed coastguard has also stepped up interceptions, often cutting migrant boats off before they can reach international vessels that would bring them to Europe.

In Libya, many migrants are detained, tortured and even killed, according to IOM. At least 20,000 migrants are being detained in Libya, which is the main gateway for Africans to reach Europe. Images broadcast by CNN earlier this month appeared to show migrants being auctioned off as slaves by Libyan traffickers, sparking outrage in Europe and anger in Africa. Numbers of detainees swelled after boat departures for Italy from the smuggling hub of Sabratha were largely blocked this year. The EU, U.N. and African Union agreed last year to an emergency plan to dismantle people smuggling networks and repatriate stranded migrants in an effort to ease a human rights disaster in Libya. Compiled from wires