U.S.-led coalition forces say the Russian-backed Syrian army has crossed the Euphrates River in Deir el-Zour in its bid to regain control of the Syrian city, a move that could result in a faceoff with U.S.-backed fighters in the city's east.
"We confirm Russian and Syrian regime forces have moved east of the Euphrates River," Colonel Ryan Dillon, a spokesman for the U.S.-led coalition, told VOA on Tuesday. "The Russians are providing air support to Syrian regime operations to reclaim territorial control over the area around [Deir el-Zour]."
The campaign for Deir el-Zour, one of the Islamic State militant group's major strongholds in Syria, began this month. The Syrian army, supported by Shi'ite militias and Russian air power, began advancing from the western side of the city and broke a three-year IS siege of an enclave the regime had controlled.
Meanwhile, the U.S.-backed Syrian Democratic Forces (SDF) started a separate operation from east side of the city. They made rapid gains, capturing 300 square kilometers along the eastern riverbank.
The Euphrates River, which runs across the city, acted as a dividing line between the two sides, and was considered part of the deconfliction zone between the U.S.-led coalition and Russia, intended to separate their areas of operation in Syria and prevent inadvertent clashes.
According to SANA, the Syrian state-run news agency, the Syrian army crossed the river using specially constructed pontoon bridges, as Russian warplanes provided aerial protection.
The news agency said Syrian army units have secured several points in Mazloum and Marrat villages on the eastern side of the city, and reportedly have advanced toward a major gas field known as Conoco.
"IS endured heavy losses in arms and men," SANA reported.
Amaq, Islamic State's media wing, confirmed the development. It claimed militant fighters had carried out suicide attacks that trapped dozens of the advancing troops in Marrat village.
Earlier this month, the U.S.-led coalition said it was closely monitoring the Syrian army's approach to the river. There are concerns about possible clashes on the river's eastern bank between Syrian army units and the SDF.
SDF commanders said they had taken fire from Syrian regime forces even before they crossed the Euphrates.
On Saturday, a Russian airstrike wounded six SDF fighters in an industrial area that had been recaptured from IS militants near the river. Coalition troops advising and assisting the SDF were present but unhurt, according to a statement by the U.S.-led coalition.
The attack "underscores the need for all parties to recommit themselves to deconflict their operations responsibly and professionally," Dillon told VOA. He said the U.S.-led coalition would continue to communicate with Russian forces to ensure the separation of forces does not collapse entirely, and that all sides keep focusing on defeating Islamic State.