The US and its partner forces have carried out large-scale strikes against Islamic State (IS) group targets in Syria, the US Central Command (Centcom) has announced.

US President Donald Trump directed the strikes on Saturday, which are part of Operation Hawkeye Strike, in retaliation to the IS's deadly attack on US forces in Syria on 13 December, Centcom wrote on X.

The strikes were conducted in an effort to combat terrorism and protect US and partner forces in the region, according to Centcom.

"Our message remains strong: if you harm our warfighters, we will find you and kill you anywhere in the world, no matter how hard you try to evade justice," Centcom said.

The US and its partner forces fired more than 90 precision munitions at more than 35 targets in an operation that involved more than 20 aircraft, an official told CBS News, the BBC's US partner.

The official added that aircraft including F-15Es, A-10s, AC-130Js, MQ-9s and Jordanian F-16s had taken part in the strikes.

The location of the strikes and the extent of any casualties is not yet clear.

"We will never forget, and never relent," Defence Secretary Pete Hegseth wrote on X on Saturday in reference to the military action.

The Trump administration first announced the Operation Hawkeye Strike in December after an IS gunman killed two US soldiers and a US civilian interpreter in an ambush in Palmyra, located in the centre of Syria.

"This is not the beginning of a war - it is a declaration of vengeance," Hegseth said when announcing the operation in December.

"The United States of America, under President Trump's leadership, will never hesitate and never relent to defend our people."

Prior to the latest strikes on Saturday, US forces killed or captured nearly 25 IS group members in 11 missions between 20 December and 29 December as part of Operation Hawkeye Strike, Centcom said.

In the operation's first mission on 19 December, US and Jordanian forces carried out a "massive strike" against the IS group, deploying fighter jets, attack helicopters and artillery to strike "more than 70 targets at multiple locations across central Syria", according to Centcom.

That operation, it said, "employed more than 100 precision munitions" targeting known IS infrastructure and weapons sites.

Syria has been in a fragile state since the fall of President Bashar al-Assad's regime in December 2024, which effectively ended a civil war that had ravaged the country for 13 years.

Ahmed al-Sharaa, also known by his nom-de-guerre Abu Mohammed al-Jolani, has been serving as the country's president since his rebel group ousted Assad and solidified control.

The IS has been weakened in Syria, but still remains active, predominantly carrying out attacks against Kurdish-led forces in the north-east in 2025.