Five explosions shook the US occupation base in Al-Omar oil field, Deir Ezzor after it was hit by a missile attack from an unknown source.

The sounds of explosions heard in the vicinity of the US base were the result of over five missiles striking the base, local sources told Sputnik.

"The missiles were launched from the West of the Euphrates river, southeast of Deir Ezzor, in which there are Syrian Arab Army-allied forces," the sources added.

According to the sources, US aircraft took to the skies as soon as the explosions took place.

However, a reliable source told Al Mayadeen the explosions were the result of live munition exercises conducted by the international coalition in the base.

"The coalition brought in March four batches of arms and equipment that passed through an illegal crossing between Syria and Iraq, and they distributed them in Deir Ezzor and Al-Hasakah," the source added.

The armament coincided with the coalition forces releasing around 1,200 ISIS prisoners in Al-Hasakah and Deir Ezzor.

Sources had reported to Al Mayadeen that the International Coalition and the Syrian Democratic Forces (SDF) were transferring ISIS elements from prisons south of Al-Hasakah and north of Deir Ezzor. 

In January, the International Coalition, in a statement, revealed that the US-backed SDF had taken over Ghuwayran prison in Al-Hasakah and moved ISIS militants to a fortified facility.