US aircraft carrier strike group arrives in Middle East

Syrian rebel forces said late Tuesday they had taken control of the eastern city of Deir el-Zour on the banks of the Euphrates River and close to U.S. military positions in the region.

The city was occupied by Kurdish-led Syrian Democratic Forces on Dec. 6 as former president Bashar Assad's forces withdrew. The SDF subsequenty faced protests from residents and local officials.

The Hayat Tahrir al-Sham Military Operations Department said in a post to Telegram that the city and its military airport were "completely liberated" as of the early hours of Wednesday.

Geolocated videos showed rebel fighters in the city center, joined by residents waving the Syrian revolutionary flag.

Rebel forces continued to advance into the countryside to the west and east of the city, Lt. Col. Hassan Abdul Ghani said in a statement posted to Telegram.

Deir el-Zour is the largest city in eastern Syria and the closest to U.S. troop concentrations along the Euphrates River running to the Iraqi border.

-ABC News' Helena Skinner

Iranian Supreme Leader Ayatollah Ali Khamenei alleged on Wednesday that the U.S. and Israel orchestrated the rapid collapse of the Syrian government led by former President Bashar Assad.

Damascus' defeat, Khamenei wrote on X, "was planned in the U.S.-Israeli control room."

"We have evidence for this" which leaves "no room for doubt," Khamenei said.

Iran and Russia were the key backers of Assad's government through more than a decade of civil war.

Tehran's support for the regime in Damascus enabled Iran's Islamic Revolutionary Guard Corps to establish a major presence inside Syria alongside a range of Iran-backed militias, including Lebanese Hezbollah.

After dedicating his life to fighting the Assad regime, Mazen Al-Hamada did not live to see it fall.

A symbol of resilience and courage, the famous Syrian activist was found dead in the "slaughterhouse" prison of Saydnaya in Damascus, where he had been held since he returned to Syria in February 2020.

An unverified photo circulating online shows his disfigured face and suggests he was killed just before the rebels reached the prison, according to independent observers.

Al-Hamada was first arrested in 2011, when he protested against the regime, and remained in prison for two years. He left Syria in 2013 and was granted asylum in the Netherlands a year later.

That's when the world got to know the horrors he endured, which he bravely described as he spoke to huge crowds, policymakers and the press, voicing the struggle of thousands who like him were detained by Assad's regime -- at least 157,000 between 2011 and August 2024, according to a report by the Syrian Network for Human Rights.

“I will not rest until I take them to court and get justice,” Al-Hamada said in an interview for a 2017 documentary, ‘Syria's Disappeared,’ his sunken eyes in tears unable to hide the pain behind his words. “Justice for me and my friends who they killed. Even if it costs my life. Bring them to justice, no matter what."

-ABC News' Camilla Alcini

The White Helmets said they have searched a second prison in Damascus within a training center for the Assad regime's State Security Branch.

"Our teams conducted searches and inspections inside the prison and the basement, which contains collective and solitary confinement cells, where innocent people were detained and brutally tortured. The teams found papers with numbers of soldiers who worked in the branch. The teams contacted them and they confirmed that the cells were only within the basement and that there were no hidden detention centers in the place," the White Helmets said in a statement.