Four migrants were found dead and three were missing after their off the Libyan coast, the North African country's coast guard said Tuesday.
The agency also rescued 13 migrants who had been shipwrecked as they tried to , it said in a statement.
"The rescued migrants were taken to the Mellitah landing point and handed to the competent authorities," it said, adding steps would be taken to send them "back to their countries".
Twelve of the rescued migrants were Syrian, along with one Egyptian, a navy official told AFP.
The nationalities of those who died, three men and a woman, were unknown.
Libya's descent into lawless chaos after the 2011 revolt that toppled the regime of Muammar Gaddafi turned the country into a major conduit for refugees from across the Arab world, Africa and even South Asia seeking to reach Europe.
Many who board unseaworthy boats headed for Italy, 300 kilometres (185 miles) away, die in the process, making it the deadliest migration route in the world.
Several thousand are also trapped in Libya, often facing severe human rights violations.
Since the start of the year, 6,340 migrants have been intercepted and returned to Libya, according to figures published by the United Nations' migration agency on Monday.
Meanwhile at least 129 people have died attempting the crossing and 459 have gone missing, it said.