BEIRUT (AP) — The U.N. children's agency warned Friday that the fight for the Islamic State group's stronghold of Raqqa threatens more than 40,000 children, while overnight airstrikes on the city in northern Syria killed more than a dozen people.
The violence has displaced residents in and around the city, with about 80,000 children living in temporary shelters and camps, UNICEF said in a statement.
The U.S.-backed Syrian Democratic Forces launched an attack on Raqqa earlier this week and airstrikes by the U.S.-led coalition have intensified since then.
"An estimated 40,000 children remain trapped in extremely dangerous conditions in Raqqa. Many are caught in the crossfire," said UNICEF regional director Geert Cappelaere. He urged all parties to give safe passage to those who want to leave.
The Britain-based Syrian Observatory for Human Rights reported more than 25 overnight airstrikes on Raqqa killed 17 people, including 12 at an internet cafe. One of the dead was an activist with the group, it added.
In addition to the airstrikes, Raqqa was subjected to artillery and missile attacks, according to the activist collective known as Raqqa is Being Slaughtered Silently. It said the coalition used white phosphorous in the attacks.
In a video posted on its Aamaq news agency, IS also alleged the coalition used white phosphorous over Raqqa on Thursday at dusk, when Muslims would have been breaking their Ramadan fasts.
White phosphorous burns at extremely high temperatures and can be used to illuminate conflict zones or obscure them with smoke. International law prohibits its use in civilian areas because of its indiscriminate effects — from starting fires to causing excruciating burns for bystanders, according to Human Rights Watch, which said it was investigating the allegations.
The U.S. CENTCOM military command refused to comment on specific allegations but said it uses white phosphorous rounds "in accordance with the law of armed conflict ... in a way that fully considers the possible incidental effects on civilians and civilian structures."
The violence came as Syrian troops and their allies have been clashing in southeastern Syria with U.S.-backed rebels near the border with Iraq. The Observatory said rebels attacked government forces near the area where the Syrian, Jordanian and Iraqi borders meet.
On Thursday, a drone that U.S. officials say was likely connected to Iranian-supported Hezbollah forces fired on U.S.-backed troops and was shot down by an American fighter jet in southern Syria near a base where the coalition is training Syrian rebels fighting the Islamic State group.
U.S. defense officials said the weapon fired by the drone did not detonate and no one was hurt.
Earlier this week, the U.S. bombed similar forces inside the protected zone after an attack by another unaffiliated group of Syrian rebels. The pro-government forces brought in additional equipment and called in airstrikes to repel the assault, and the U.S. was informed of those developments through the so-called "deconfliction line" it has set up with the Russian military.
Associated Press writer Maamoun Youssef in Cairo contributed to this report.