Al Mayadeen sources reported on Saturday that a delegation from the International Coalition visited the Central Prison in the Syrian province of Raqqa, which houses detainees from the elements of the ISIS organization. 

Read more: International coalition, SDF transfer ISIS prisoners

"Elements of the Syrian Democratic Forces (SDF) and the Kurdish internal security forces (Asayish) are on high alert in the city of Raqqa with the closure of most roads leading to it," the sources said.

The sources also pointed out that, "there are no clear reasons for the visit of the coalition delegation, which also visited the cities of Manbij and Ayn Al-Arab in the countryside of Aleppo over the past two days."

Read more: US occupation base in Al-Tanf Syria targeted with drone attack

Last April, Syria sent a letter to UN Secretary-General Antonio Guterres and to the UN Security Council about the war crimes of the US-led international coalition in the city of Raqqa in 2017.

The letter stressed that the goal of the coalition's operation was to destroy infrastructure and public and private property and target civilians in Raqqa, Ayn Al-Arab, and Al-Baghouz, highlighting that US official sources have admitted to the killing and injuring of 240 civilians in the city.

Read more: Several killed, others injured in terrorist attack on bus in Raqqa

Al Mayadeen sources reported last June that the Raqqa Central Prison was attacked at dawn and that up to hundreds of prisoners, including ISIS members, escaped.

The US military has been 2017 illegally controlling territories in the north and northeast of Syria in the provinces of Deir Ezzor, al-Hasakah, and Raqqa, where the largest oil and gas fields in Syria are located.

Damascus has repeatedly deemed the presence of the US military on its territory as an occupation and state piracy with the aim of outright theft of oil.

Read more: Terrorists flee prison, 1000+ families displaced in al-Hasakah