The Italian coastguard has rescued more than 2,000 migrants in a major operation off the Libyan coast, officials said.
During the rescue, search teams were threatened by Kalashnikov-wielding men who approached in a speedboat from Libya, Italian officials said.
According to Italy's transport ministry, four men with Kalashnikov rifles sped out from the Libyan shore during the rescue and ordered the coastguard to return a boat that had been emptied of migrants.
Local media reported that the migrants had been aboard 12 boats and had been taken to Italy.
On Friday another 600 migrants were rescued about 50 miles (80km) off the coast of the North African country.
The UNHCR said almost 3,500 people died attempting to cross the Mediterranean Sea to reach Europe in 2014, making it the world's most dangerous sea crossing for migrants trying to enter the European Union.