An airstrike hit a detention center for migrants near the Libyan capital early Wednesday, killing at least 44 people and wounding more than 130, the U.N. mission to the war-torn country said.
The airstrike raises further concerns about the European Union's policy of partnering with Libyan militias to prevent migrants from crossing the Mediterranean, which often leaves them at the mercy of brutal traffickers or stranded in squalid detention centers near the front lines.
It could also lead to greater Western pressure on Khalifa Hifter, a Libyan general whose forces launched an offensive on Tripoli in April. The Tripoli-based government blamed his self-styled Libyan National Army for the airstrike and called for the U.N. to investigate.
A spokesman for Hifter's forces did not immediately answer phone calls and messages seeking comment. Local media reported the LNA had launched airstrikes against a militia camp near the detention center in Tripoli's Tajoura neighborhood.
Footage circulating online and said to be from inside the migrant detention center showed blood and body parts mixed with rubble and migrants' belongings.
The airstrike hit a workshop housing weapons and vehicles and an adjacent hangar where around 150 migrants were being held, mostly Sudanese and Moroccans, according to two migrants who spoke to The Associated Press on condition of anonymity for fear of reprisal.
The migrants said three or four survived unharmed and about 20 were wounded. They said the rest were killed, indicating the final death toll could be much higher.
Doctors Without Borders said the detention cell that was destroyed held 126 migrants. The aid group's Libya medical coordinator, Prince Alfani, said teams visited the center just hours before the airstrike. He said survivors fear for their lives, and he called for the immediate evacuation of the detention centers.
The U.N. refugee agency also condemned the airstrike and called for an immediate end to efforts to return migrants to Libya.
UNHCR spokesman Charlie Yaxley noted that the agency had warned less than two months ago that anyone inside the Tajoura detention center was at risk of being caught in the fighting around Tripoli. Then, an airstrike that hit nearby wounded two migrants. Yaxley said UNHCR is sending medical teams to the site after the latest airstrike.
The head of the African Union, Moussa Faki Mahamat, also condemned the strike. He called for an independent investigation and said those responsible for the "horrific crime" should be held to account.
The LNA launched an offensive against the weak Tripoli-based government in April. Hifter's forces control much of Libya's east and south but suffered a significant blow last week when militias allied with the Tripoli government reclaimed the strategic town of Gharyan, about 100 kilometers (62 miles) from the capital. Gharyan had been a key LNA supply route.
Hifter's forces have targeted militia positions in Tajoura with airstrikes in recent weeks. The LNA said Monday it had begun an air campaign on rival forces in Tripoli after it lost control of Gharyan.
Hifter's forces boast MiG fighter jets supplied by neighboring Egypt, as well as drones, attack helicopters and mine-resistant vehicles. It was not immediately clear what munitions were used in the airstrike early Wednesday.
Oded Berkowitz, a security analyst focused on the Libyan conflict, said Hifter's LNA flies "a handful of obsolete aircraft" that are "in poor condition." He said it has received spare parts from Egypt and possibly Russia, as well as decommissioned aircraft from both countries.
"Egypt and the UAE have been conducting air operations on behalf of the LNA, but there are no indications that the UAE transferred aircraft to the LNA," he said.
Fathi Bashagha, the interior minister in the Tripoli-based government, claimed that foreign countries allied with Hifter were behind the attack. He told The Associated Press that Hifter's foreign backers "went mad" after his forces lost Gharyan. He did not name any countries or provide evidence to support his claim. He also denied any weapons were being stored at the detention facility.
The fighting for Tripoli has threatened to plunge Libya into another bout of violence on the scale of the 2011 conflict that ousted longtime dictator Moammar Gadhafi and led to his death.
Hifter says he is determined to restore stability to the North African country. He is backed by Egypt, the United Arab Emirates and Saudi Arabia while his rivals, mainly Islamists, are supported by Turkey and Qatar.
His campaign against Islamic militants across Libya since 2014 won him growing international support from world leaders who are concerned that Libya has become a haven for armed groups and a major conduit for migrants bound for Europe.
His opponents, however, view him as an aspiring autocrat and fear a return to one-man rule.
Libya became a major crossing point for migrants to Europe after Gadhafi's overthrow, when the North African nation was thrown into chaos, armed militias proliferated and central authority fell apart.
At least 6,000 migrants from Eritrea, Ethiopia, Somalia, Sudan and other nations are locked in dozens of detention facilities in Libya run by militias accused of torture and other abuses. Most of the migrants were apprehended by European Union-funded and -trained Libyan coast guards while trying to cross the Mediterranean Sea to Europe.
The detention centers have limited food and other supplies for the migrants, who often end up there after arduous journeys at the mercy of abusive traffickers who hold them for ransom money from families back home.
The U.N. refugee agency has said that more than 3,000 migrants are in danger because they are held in detention centers close to the front lines.
Associated Press writer Maggie Michael contributed.