German, Libyan rescue-ships duel to save imperilled migrant boat
The 493 migrants included 277 from Morocco and many from Bangladesh. 20 women and a child were aboard the boat. All were taken to a naval base in Tripoli.
There were also migrants from Syria, Tunisia, Egypt, Sudan, Pakistan, Chad, Mali and Nigeria, said navy spokesman Ayoub Qassem.
The migrants, who were bound for Italy, were picked up off the western city of Sabratha.
The German non-governmental organisation "Sea-Watch tried to disrupt the coastguard operation... inside Libyan waters and wanted to take the migrants, on the pretext that Libya wasn't safe," Qassem told AFP.
Sea-Watch posted a video on Twitter of what it said was a Libyan coastguard vessel narrowly cutting across the bow of its ship.
"This EU-funded Libyan patrol vessel almost crashed (into) our civil rescue ship," read the caption.
Qassem also said the coastguard had come under fire from people traffickers, without reporting any casualties.
According to international organisations, between 800,000 and one million people, mostly from sub-Saharan Africa, are currently in Libya hoping to make the perilous Mediterranean crossing to Europe.
'Marketplace for human trafficking'
But an immigration official said between 7,000 and 8,000 migrants are being held in harsh conditions in detention centres across Libya after entering the country illegally.
The North African country has long been a stepping stone for migrants seeking a better life in Europe, but most have fallen into the hands of smugglers and human traffickers.
Smugglers have stepped up their lucrative business in the chaos which has engulfed Libya since its 2011 revolution.
Thousands of vulnerable migrants - including women and children - are being held in detention centres where "crimes, including killings, rapes and torture, are alleged to be commonplace", the International Criminal Court's chief prosecutor said last week.
Noting that Libya's overall security has "deteriorated significantly" since last year, Fatou Bensouda warned that migrant-smuggling could help organised crime and terror networks expand their hold in the North African country.
Last month, Italian prosecutors made extraordinary claims, accusing aid groups in Libya of working with brutal human traffickers that operate in the war-torn country.
Doctors Without Borders (Medecins Sans Frontiers), SOS Mediterranee, Save the Children and Mobile Offshore Aid Station (MOAS) are some of the NGOs who have denied being in collusion with traffickers.
The number of people leaving Libya to reach Europe is up nearly 50 percent this year compared with the opening months of 2016.
Agencies contributed to this report.