(CNN) - An airstrike that hit a migrant detention center near the Libyan capital early Wednesday has left at least 40 people dead and another 200 injured, a health official in the country's UN-recognized government told CNN.
"I expect the death toll to go up given that there are critically injured people being treated in hospital," Malek Merset, a spokesman for the Ministry of Health, said.
Satellite images taken of the detention center in Tajoura, a coastal town east of Tripoli, showed extensive damage to several buildings in the complex. Photos taken on the ground captured piles of rubble left where structures had been, while emergency crews worked to remove both the wounded and the dead.
Libya's Government of National Accord (GNA) condemned the "horrific crime," blaming renegade Gen. Khalifa Haftar, leader of the Libyan National Army (LNA), whose forces have been waging an assault on the capital for the last two months.
The LNA has denied responsibility for the attack, instead accusing Tripoli-based "militias" -- who are largely allied to the GNA -- of orchestrating a "conspiracy" to "tarnish" their reputation.
"The militias have, in the past, targeted civilians in Tripoli and blamed the LNA, but they failed ... what they have done today is nothing but propaganda," LNA spokesman Ahmed al-Mismari said Wednesday during a press conference, calling for an independent investigation into the attack.
There has been no independent confirmation of who is responsible for the airstrike, which the GNA said constituted a "war crime."
"We ask the international community through the African Union, European Union and (other) organizations to take a firm and clear stance against these continued violations," the GNA statement read.
Italy's Foreign Ministry and the African Union have also condemned the strike.
The UN Security Council is holding closed-door consultations on the attack Wednesday afternoon, a UN diplomat told CNN.
UN Secretary General António Guterres has called for an independent investigation into the "horrendous" incident and has reiterated his call for an immediate ceasefire in Libya. "We need to see a halt to the fighting, a return to negotiations," his spokesman, Stéphane Dujarric, said.
The strike marks the second time that the Tajoura detention center, which houses around 600 migrants, has been hit during the ongoing conflict, according to the UN High Commissioner for Human Rights Michelle Bachelet.
"The fact that the coordinates of this detention facility and the knowledge that it housed civilians had been communicated to the parties to the conflict indicates that this attack may -- depending on the precise circumstances -- amount to a war crime," Bachelet said in a statement on Wednesday.
Some 3,300 people are arbitrarily held in centers around Tripoli, a transit point along the central Mediterranean migrant route, according to the International Organization for Migration and UNHCR. Migrants in the facilities face overcrowding, abuse and forced labor.
Many who get stuck there are intercepted and detained by Libyan coast guards, who are funded and trained by the European Union, while trying to make it across the Mediterranean.
"The EU's decision to withdraw the naval assets in Operation Sophia that provided a vital role in saving lives at sea has meant that thousands more people find themselves trapped in detention centers like Tajoura," Elinor Raikes, regional director for the IRC in Europe and North Africa, said.
"Detention is not the answer to the protection of people on the move and Europe and the US must find alternative and sustainable solutions for the most vulnerable people," she added
And the situation for migrants stuck in centers has become worse since the armed conflict in and around Tripoli escalated on April 4, when Haftar's forces launched an offensive to capture the Libyan capital from the UN-recognized government. More than 105,000 people have been displaced in the conflict, according to the International Rescue Committee.
Defending the capital are disparate Islamist militia that prop up the UN-recognized transitional government.
Human rights organizations said that they have seen both sides potentially committing war crimes, including indiscriminate attacks on residential areas and migrant detention centers.
The UN Security Council has voted to impose an arms embargo against Libya until June 2020, saying that there is "no military solution" to the ongoing conflict.
But Amnesty International said that the embargo is not being properly enforced and has accused Jordan, the United Arab Emirates and Turkey of flouting the ban.
US Sen. Bob Menendez, D-New Jersey, sent a letter to Secretary of State Mike Pompeo on Sunday expressing "deep concern" about reports that the UAE had transferred "US-origin Javelin missiles" to Haftar.
On Tuesday, the Emirati Ministry of Foreign Affairs denied ownership of weapons found in Libya, and said it remained committed to the UNSC resolution on Libyan sanctions and the arms embargo. The foreign ministry statement didn't mention Menendez's letter.
CNN's Richard Roth and Eliza Mackintosh in New York contributed to this report.
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