The US military struck ISIS targets in Syria on Sunday as rebel groups toppled the government.

Longtime Syrian leader Bashar Assad fled Damascus for Moscow.

President Joe Biden said US forces would remain in Syria to fight ISIS.

The US military said it carried out dozens of precision strikes against ISIS targets in central Syria on Sunday.

The widespread airstrikes came after a dayslong blitz by rebel forces that ultimately led to the downfall of Syria's longtime leader, Bashar Assad. Russian state news media reported Sunday that Assad had arrived in Moscow, where he was given asylum.

US Central Command, which oversees Middle East operations, said it struck ISIS leaders, operatives, and camps to prevent the terrorist group from rebuilding in central Syria amid the chaos.

Centcom said it used US Air Force B-52 bombers, F-15 fighter jets, and A-10 attack aircraft to strike over 75 targets, adding that battle damage assessments are underway. A senior administration official, speaking to reporters, described the operation as "significant" and said about 140 munitions were used. It is unclear what missiles or bombs may have been used.

"There should be no doubt — we will not allow ISIS to reconstitute and take advantage of the current situation in Syria," Gen. Michael Erik Kurilla, the Centcom commander, said in a statement. "All organizations in Syria should know that we will hold them accountable if they partner with or support ISIS in any way."

Syrian anti-government forces announced early on Sunday morning that they had taken control of Damascus. It was the culmination of 13 years of civil war, which began in 2011 after Assad's forces violently cracked down on peaceful demonstrators.

Hayat Tahrir al-Sham, an organization that traces its origins to Al Qaeda but has since split from the group and portrayed itself as more moderate, launched the surprise offensive in late November. The rebels quickly took control of Aleppo, one of Syria's largest cities, Hama, and the strategic city of Homs before advancing into Damascus.

President Joe Biden, in a press briefing on Sunday, acknowledged that the US conducted airstrikes "targeting ISIS camps and ISIS operatives" inside Syria.

"We're clear-eyed about the fact that ISIS will try to take advantage of any vacuum to re-establish its capability to create a safe haven," Biden said. "We will not let that happen."

Biden said that the US would support Syria's neighbors Jordan, Lebanon, Iraq, and Israel "should any threat arise from Syria during this transition."

The United States has about 900 troops in Syria carrying out missions against ISIS. Biden said on Sunday that these forces will remain in the country despite Assad's ouster.

The US routinely works with local forces in Syria and neighboring Iraq to carry out operations against ISIS, dozens of which have taken place in recent months.