"Coast Guards patrols rescued a total of 391 on rubber boats during the past four days off northeastern Tripoli," Ayob Qassem, navy's spokesman, told Xinhua.
The rescued immigrants are of different Arab, African and Asian nationalities, the spokesman said.
The immigrants have been provided with humanitarian and medical assistance and taken to a reception center in the city, Qassem added.
Libyan navy rescued more than 1,200 illegal immigrants off the western coast in May.
Recently, migrant flows from western Libya toward Europe have increased significantly because of the improved weather conditions.
Libya is a preferred point of departure for illegal immigrants who want to cross the Mediterranean toward Europe because of the insecurity and chaos in the North African country.
