Pro-Assad forces are advancing again towards US-supported rebels in eastern Syria, days after American warplanes tried to deter an offensive by bombing a convoy with Hezbollah fighters, Iraqi militiamen, and — reportedly — Iranian troops.

The pro-Assad units are moving in the Badia, a desert region near Syria’s southern border with Iraq. Free Syrian Army factions, trained and assisted by US special forces, are positioned at a base near the town of Tanf.

Over the weekend, the pro-Assad forces advanced in Suweida Province, about 110 km (68 miles) west of Tanf, capturing the Zalaf Dam and several small settlements.

A rebel spokesman said the offensive had been checked but “the battle continues until this very moment”.

Meanwhile, Iranian-supported militias moved south from the eastern Qalamoun area.

The US airstrikes last Thursday reportedly caused dozens of casualties, destroying an armored vehicles and engineering trucks. An American military spokesman said Sunday that deterrent strikes would again be carried out:

If pro-regime forces move further south or east from their current positions, this will be considered a threat. Coalition forces will defend themselves.

On Monday the Free Syrian Army said it would respond with Operation Badia Volcano to “cleanse the Badia of Iranian and foreign militias”.

The FSA, with the US military support, has taken more than 2,500 square km in the Badia from the Islamic State in recent months. However, the Assad regime is hoping to move along the Damascus-Baghdad highway to connect its territory with Deir ez-Zor Province, where ISIS has surrounded regime forces since 2014.

SYRIA BADIA MAP

Map: Syria Direct

TOP PHOTO: Fighters with the Free Syrian Army faction Maghwair al-Thawra in the Badia region in eastern Syria