Several humanitarian organizations called on Monday for the immediate rescue of the sinking boat off the coast of Libya, with 100 migrants on board.

The head of the European Union delegation to Libya, Sabadell Jose, strongly condemned the "heinous killing" of the 15 migrants in Sabratha.

"We are also deeply saddened by the tragic loss of human life. Our thoughts are with the victims and their families," said the official.

Jose called, via his Twitter account, for "a swift, independent and transparent investigation to bring all perpetrators to justice. We must continue to fight the criminal networks that exploit migrants and asylum-seekers in Libya."

Reports varied about the incident; some eyewitnesses said the dead people were migrants caught in a dispute between two rival groups of people smugglers, while others declared an artillery shell that attacked the boat.

The Libyan Red Crescent Society, which led the rescue mission, did not reveal any details, saying its efforts are limited to providing humanitarian support to local authorities and alleviating the suffering of the most vulnerable groups.

The British Ambassador to Libya, Caroline Hurndall, called for an investigation into this "abhorrent” incident and bringing the perpetrators to justice, adding that the criminal networks that exploit migrants and asylum-seekers must be dismantled.

The UN said that 11 charred bodies were found inside the docked boat, with four wounded bodies found outside, noting that the exact circumstances have not been determined.

The statement indicated that the killings reportedly resulted from armed clashes between rival traffickers.

UNSMIL called on "Libyan authorities to ensure a swift, independent and transparent investigation to bring all perpetrators to justice," adding that the attack is a "stark reminder" of the lack of protection migrants and asylum-seekers face in Libya, and the "widespread human rights violations undertaken by powerful trafficking and criminal networks who need to be swiftly stopped and prosecuted."

Furthermore, the US Embassy in Libya also strongly condemned the incident, calling on the Libyan authorities to "swiftly investigate this horrific attack, prosecute the criminals involved, and intensify efforts to combat human trafficking to the fullest extent."

Sabratha is one of the major transit points for illegal migrants seeking to travel to Europe.

Since the start of the year, more than 14,000 migrants have been intercepted and returned to Libya, according to the International Organization for Migration (IOM).

At least 216 people have died attempting to cross the Mediterranean Sea, and 724 are missing and presumed dead.

The Red Crescent recovered dozens of bodies washed ashore in Khoms city in November 2020, which the group described as a terrifying disaster at the time.

The Red Crescent pointed out that it works with regional and international partners to support and assist migrants, stressing that it will continue to support migrants and displaced persons all over Libya by providing health services and ensuring communication with their families.

Meanwhile, SOS Mediterranee and the ALARMPHONE project issued a joint call to rescue a boat carrying 100 migrants off the Libyan coast.

The appeal, which was reported by the Italian agency "Aki," stated that a hundred people are at risk off the coast of Libya after losing contact with them, pointing out that before the communication was cut off, one of the migrants reported to the two sides that the boat's engine failed and water started leaking into the ship.