March 1 (UPI) -- Backed by Russian air cover, the Syrian Arab Army on Wednesday liberated the key Palmyra Triangle, in the eastern desert of Syria, from Islamic State rule, officials said.
The armed forces of Syrian President Bashar Assad attacked Islamic State defenses on the western perimeter of the triangle, authorities said, which is located in Homs Governorate in the expansive Syrian desert.
After a two-hour fight, the army said it liberated the triangle zone and advanced to within two miles of the Palmyra city limits.
Military forces are also targeting Islamic State positions and supply lines in nearby Deir Ezzor.
Islamic State militants have been fighting in the Palmyra region for years, where ancient and historical landmarks have been destroyed outright by the terror group.
A number of militants were killed and wounded in Wednesday's battle, the army said, and Syrian forces continued to chase down fleeing insurgent fighters.
Moscow has been aiding Syria's army in the fight with coordinated airstrikes for many months.
Also Wednesday, the U.S. Department of Defense said a Russian airstrike bombed a location about 130 miles to the northwest, near Aleppo -- causing an undetermined number of casualties of U.S.-led coalition troops.
"We had some Russian aircraft and regime aircraft bomb some villages that I believe they thought were held by ISIS," Lt. Gen. Stephen Townsend, commander of the U.S.-led task force in Iraq and Syria, told reporters in a video call from Baghdad. "Actually on the ground were some of our Syrian Arab coalition forces."
Townsend said American military advisers were positioned about three miles away when the strike occurred on Tuesday.
The Russian government, though, has denied the claim.
"To avoid any incidents, the U.S. representative has provided exact coordinates of the U.S.-backed opposition forces in the region to a Russian officer," Moscow's defense ministry said in a statement Wednesday. "Not a single airstrike on the regions specified by the U.S. side was conducted by Russian or Syrian air forces."
If true, the errant Russian strike is the second by Moscow in recent weeks in the fight against the militant group, also known by the acronyms ISIS and ISIL. Last month, Russian jets mistakenly bombed Turkish forces near Al-Bab.
"The coalition is encouraged by the progress against ISIS in Al Bab by the Turkish military and their opposition forces," Townsend said. "We encourage all forces to remain focused on the counter-ISIS fight and concentrate their efforts on defeating ISIS, and not toward other objectives that may cause the coalition to divert energy and resources."