Targets in Syria hit by U.S. airstrikes earlier this week were critical facilities for Iranian-linked groups operating in the country, experts said.

The U.S. military said late Tuesday it carried out strikes in eastern Syria against “infrastructure facilities used by groups linked to Iran’s Islamic Revolutionary Guard Corps [IRGC].”

“Today’s strikes were necessary to protect and defend U.S. personnel. The United States took proportionate, deliberate action intended to limit the risk of escalation and minimize the risk of casualties,” U.S. Central Command Communication Director Colonel Joe Buccino said in a statement Tuesday.

The U.S. official added that the airstrikes in the province of Deir el-Zour were carried out to protect U.S. forces from attacks, including one on August 15 in eastern Syria, which the U.S. said involved a drone that targeted a compound run by U.S. troops and U.S.-backed Syrian opposition fighters.

The military has not said whether the strikes resulted in any casualties. Iran on Wednesday denied having any links to those targeted in the U.S. airstrikes in Syria.

Iran is a staunch supporter of Syrian President Bashar al-Assad’s regime and has a significant military presence in areas along the Syria-Iraq border.

Experts say the facilities hit by the U.S. were military depots used for Iran’s military activities in the region.

“These military depots are strategically important for Iran as they are located on the Syria-Iraq border, which gives Iran access to a vast area in both countries,” said Omar Abu Layla, director of Deir Ezzor 24, a monitor group focused on developments in eastern Syria.

“Iran relies on these facilities to carry out attacks against American forces that are stationed on the eastern side of the Euphrates River,” he told VOA, noting that his network had recently confirmed “the arrival of several Iranian military shipments, including drones and mid-range missiles” to the warehouses that were hit by the U.S. on Tuesday.

While the U.S. military has not indicated what targets it has struck in eastern Syria, Deir Ezzor 24 and other local news networks have reported the Ayyash military depot complex was the main target.

Bashir al-Abbad, a Syrian journalist, told the U.S.-funded Alhurra television that “these are large warehouses that have 80 buildings located in a desert area south of the town of Ayyash” in Deir el-Zour.

The control of Deir el-Zour is divided between U.S.-backed Syrian Democratic Forces on the eastern side of the Euphrates and Iranian- and Russian-backed Syrian government forces on the western side of the river.

The U.S. has about 900 troops in northeast Syria, including Deir el-Zour, as part of a global coalition against Islamic State, or ISIS, militants.

Iran’s foreign ministry condemned the Tuesday attack and denied any link between Tehran and the targeted facilities in eastern Syria.

Nasser Kanaani, a spokesman for Iran’s foreign ministry, said in a statement Wednesday the U.S. attack was against the Syrian people, accusing the U.S. of violating Syria’s sovereignty.

The Syrian government has not immediately commented on the attack.

Myles Caggins, an analyst at the Council on Foreign Relations and a former spokesperson for the U.S.-led coalition against IS, said the U.S. strikes are a sign that Washington is still seriously engaged in defending its forces and allies in the region.

“It is very clear that the reason for the U.S.-led coalition presence in Syria is to keep ISIS from making a comeback, and attacks by adversary militia forces are a disruption, a distraction and can be deadly,” he told VOA.

After a decade of conflict, Caggins said, Syria continues to be a contested environment for groups vying for control.

This story originated in VOA’s Kurdish Service.