Charities SOS Mediterranee and Sea-Watch accused Libya's coast guard of firing gun shots and deliberately endangering the crew of SOS Mediterranee's Ocean Viking search and rescue vessel as well as persons in distress in the Central Mediterranean.

The Libyan coast guard went on to return some 80 Europe-bound migrants to Libyan soil, according to SOS Mediterranee.

The incident occurred on Saturday (March 25) in international waters, SOS Mediterranee said in a press release published on the same day. It's the latest sea interception of migrants by Libya's coast guard, news agency AP reported.

SOS Mediterranee said the Ocean Viking was warned off by the controversial government unit, which is trained and financed by the European Union to stem the influx of migrants to Europe.

Libya's coast guard was contacted by AP to comment on the situation but didn't respond.

The Italian coast guard said it had received a report about the incident, AP reported, but complained that SOS Mediterranee didn't follow correct procedures in reporting it.

Read more: 30 migrants missing in shipwreck off Libya as 1,300 arrive in Italy

What exactly are the accusations?

The Ocean Viking, a rescue ship chartered and run by the non-profit SOS Mediterranee, was responding to a distress call to help the rubber boat carrying migrants in the Central Mediterranean Sea when a Libyan coast guard vessel arrived at the scene, the charity said.

The Libyan coast guard vessel "dangerously" approached the rescue ship, threatening its crew "with guns and firing gunshots in the air," SOS Mediterranee said in the aforementioned press release.

The coast guard was caught on camera threatening the vessel and firing a weapon into the air.

In the footage, the coast guard vessel is seen traveling at a high rate of speed before maneuvering, apparently to prevent the Ocean Viking from reaching the migrant boat. At one point, gunshots are heard.

"You can't shoot at us. You can't shoot at us. We're leaving the waters now," a person on the Ocean Viking is heard saying. Under threat, the Ocean Viking sailed away while the Libyan coast guard intercepted the boat and "forcibly" took the migrants back to war-wrecked Libya, it said.

Shots fired in the direction of migrants

After the Ocean Viking forcibly retreated from the scene, Seabird 2, a civil surveillance plane owned by the German non-governmental organization Sea-Watch, reported seeing migrants who had fallen overboard from the rubber boat before the coast guard had recovered them.

In further footage shot from the charity's plane, the coast guard was seen maneuvering and approaching the rubber boat, before forcing the migrants to disembark on the coast guard vessel. Gunshots were also heard in the footage, with people on board the surveillance plane saying, "(t)hey are shooting in the water ... They are shooting at the people."

The International Organization for Migration (IOM) condemned the actions of Libya's coast guard. "Such unprovoked actions endanger lives of migrants in distress & those of rescue teams operating in the deadliest migratory sea route," the UN agency wrote on Twitter.

Read more: Sea-Watch said Libyans threatened to shoot down its plane

Hostile place for migrants

Saturday's incident was the latest report from European NGOs operating in the Mediterranean Sea of threats or violent behavior by Libya's controversial coast guard, which is one of Europe's partners to help stem migration.

Since 2015, the European Union has given more than $450 million to the unit to curb departures from Libyan soil, while also providing assistance to naval operations. Migrants intercepted by authorities are brought back to Libya, where they are placed in detention centers run by the government.

According to the IOM, Libyan authorities have intercepted and returned some 3,500 people to Libya so far this year, among them 74 children.

Libya is regularly criticized for its treatment of migrants, with UN agencies, rights groups and others alleging horrific treatment at the hands of smuggling gangs and inside state-run detention centers.

Libya has been in economical and political turmoil since the 2011 NATO-backed uprising which saw longtime autocrat leader Muammar Gaddafi removed from office.

Read more: Human Rights Watch: EU agency 'complicit' in migrant abuse in Libya

Spike in migrant arrivals to Italy 

War-ravaged Libya in northern Africa has become a hub for migrants hoping to reach Europe, as tens of thousands of people across Africa each year continue to flee conflict and poverty. Most enter Libya across the country's vast southern border in the Sahara desert, which measures over 1,500-kilometers in length.

So far this year, more than 20,000 migrants have arrived in Italy, using mainly Libya as the jumping board for their journeys. This exceeded all expectation, as only about 6,000 individuals came to Italy in the same period in each of the preceding years, according to Interior Ministry and IOM figures.

Over the weekend alone, an estimated 3,300 migrants -- many departing on small boats from Libya or Tunisia's coastal city of Sfax -- were rescued in the Mediterranean, the Italian coast guard said.

with AP