The crew of a speedboat labeled "Libyan Coast Guard" attacked a migrant boat packed with some 150 migrants, beating them with sticks and causing many to fall into the water and at least four to drown, humanitarian group Sea-Watch said on Friday.
Rescuers recovered three more dead bodies on a different rubber boat and picked up a total 3,300 survivors from 24 different boats during the day, Italy's coast guard said.
Germany-based Sea-Watch, one of several non-governmental organizations operating vessels off the coast of Libya, said the speedboat swooped in just as they were about to go to the aid of the overcrowded rubber boat in the early hours of Friday.
"The violent intervention of the Libyan Coast Guard caused a situation of mass panic on board the rubber boat in distress," Sea-Watch said in a statement. "One tube of the rubber boat collapsed, causing the majority of the 150 people to slip into the water."
The Sea-Watch crew recovered four bodies, spokesman Ruben Neugebauer told Reuters. They brought about 120 others safely onto their ship and transferred them to an oil tanker from which they were later moved to another rescue ship bound for Italy.
Four people found unconscious were given rehydration treatment and recovered enough to stand later in the day, although they still needed help to walk, Neugebauer said.
A spokesman for Libya's naval forces in Tripoli said he had not heard about the incident. A spokesman for the EU's anti-smuggling mission Sophia said they had no information about it.
An Italian coast guard spokesman said the rescues and fatalities it counted on Friday included those reported by Sea Watch. Most of the people rescued were from sub-Saharan Africa and had set off from Libya, the spokesman said.
Italy has taken in more than 146,000 boat migrants so far this year and arrivals are set to top 153,000 counted last year. Friday's rescues take the total since Sunday to about 5,500.
The rescues were carried out by the Italian coast guard, the Sophia operation, an Irish navy ship, a merchant ship, Sea Watch and four other humanitarian groups.
Libyan coast guard to be trained
It was not immediately clear if the incident would affect the planned start of training next week of up to 100 Libyan coast guard members as part of the EU mission Operation Sophia. The spokesman for Sophia had no immediate comment.
The U.S. military, which also operates ships in the region, had no immediate comment on the incident.
"Next week training starts with the Libyan coast guard," Neugebauer said. "We think it's quite important to think about with whom we are collaborating."
According to information the German government has provided to parliament, the first session of training is to take place on two ships – one Italian and one Dutch – off the coast of Libya, with equipment and trainers provided by Germany, Italy, Greece, Belgium and Britain.
The Libyan coast guard currently has three boats in Tripoli, three boats in Misrata and two boats in Zuwarah, according to the German government report. The German military said it had no information about the incident.
In August, another humanitarian group that operates rescue ships off the coast of Libya, Doctors Without Borders, said it had been attacked and boarded by armed men on a Libyan navy boat. The Libyan navy said it fired "warning shots" because it thought the ship was involved in people smuggling.