Two migrants trying to reach Europe by boat drowned off Libya on Monday, another 10 were missing and more than 100 were rescued, the coastguard said.
"We saved 108 people but two drowned and 10 others were reported missing," coastguard Colonel Ashraf al-Badri said.
"The boat was almost completely under water" off Janzour town some 10 kilometres (six miles) west of Tripoli, he said.
Those rescued had not been wearing life jackets, an AFP photographer said.
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The coastguard took them to the Tripoli naval base and gave them dry clothes, including military uniforms, and blankets as they awaited transfer to a detention centre.
Libya has for years been a stepping stone for migrants seeking to reach Europe, but smugglers have stepped up their lucrative business since the 2011 fall of Moamer Kadhafi.
Early this month, Italy's coastguard said it had rescued more than 4,600 people from unseaworthy boats off Libya in three days.
In late November, the International Organization for Migration estimated that nearly 860,000 migrants had reached Europe so far this year, but more than 3,500 had died trying to cross the Mediterranean.