BEIRUT — The U.S.-led coalition‘s failure to adequately acknowledge and investigate civilian deaths in the Syrian city of Raqqa is “a slap in the face for survivors” trying to rebuild their lives a year after the offensive to oust the Islamic State group, a prominent rights group said Friday.

At a news conference in the Lebanese capital, Amnesty International said 2,521 bodies from the battle for Raqqa have been recovered in the city, the majority killed by coalition airstrikes. It cited a small unit known as the Early Recovery Team working with U.S.-backed predominantly Kurdish forces to recover bodies and bury them. They expect to recover at least 3,000 more bodies.

There are “more bodies underneath the ground than living souls,” said Anna Neistat, Amnesty International‘s senior director of global research, who recently returned from Syria.

Coalition officials did not immediately respond to a request for comment Friday.

The battle for Raqqa, once a city of 200,000 people, played out over four months in 2017 with the coalition playing a supporting role as the Kurdish-led Syrian forces fought street by street. The coalition unleashed wave after wave of airstrikes and shell fire until the last of the militants left Raqqa in October 2017.

Amnesty has accused the coalition before of underreporting civilian deaths in the campaign to liberate Raqqa.

On Monday, Neistat said most of the bodies recovered so far are believed to be civilians.

The U.S.-led coalition said in July that 77 civilians died as a result of its airstrikes on Raqqa between June and October last year. The U.S. and its coalition partners launched their campaign against the Islamic State group in 2014, driving out the militants from their self-proclaimed capital in Raqqa three years later.

Neistat also said the “clock is ticking” for Idlib province, the last opposition stronghold in northwestern Syria. A demilitarized zone negotiated between Turkey and Russia to protect civilians from a government offensive on the northwestern province should be ready by Oct. 15.

Turkish and Russian officials have said that Syrian rebels completed withdrawing their heavy weapons from the front lines in implementation of the deal that‘s expected to demilitarize a stretch of 15-20 kilometers (9-12 miles) along the front lines by Oct. 15.

Neistat said the zone is not adequate to protect all the civilians in Idlib province and expressed concern the agreement may not last. She said she fears massive civilian deaths, destruction, displacement, arrests and disappearances, citing previous government offensives in cities like Aleppo.

Neistat called on Russia to pressure the Syrian government to take into account civilian life, pointing to Moscow‘s influence on Damascus.

“It may not be too late to stop it,” she said.

Meanwhile on Friday, Turkey‘s president Recep Tayyip Erdogan suggested that Turkey‘s military could soon launch a new operation across the border into northern Syria, in zones held by Syrian Kurdish fighters.

Erdogan‘s statement renews a threat to expand Turkey‘s military operations into areas east of the Euphrates River held by U.S.-backed Syrian Kurds.

Ankara considers the Syrian Kurdish militia to be terrorists and part of a Kurdish insurgency within Turkey.

“God willing, very soon … we will leave the terror nests east of the Euphrates in disarray,” he said. He spoke on Friday at a military ceremony honoring Turkish commandos.

Turkey launched two incursions into Syria, in 2016 and 2018, into areas west of the Euphrates, pushing Islamic State militants as well as Syrian Kurdish fighters from the border area.