TEHRAN (Press Shia Agency) – The Syrian army and its allies are fighting to secure a corridor to troops in Deir ez-Zor, a day after they smashed through Daesh (ISIL or ISIS) lines to break the militant siege.

“Work is progressing to secure the route and widen the flanks so as not to be cut or targeted by (Daesh),” said a military commander in the Syrian army, Reuters reported.

“The next step is to liberate the city,” he added.

The army reached Deir ez-Zor city on Tuesday in a days-long thrust that followed months of steady advances east across the desert, breaking a siege that had lasted three years.

Daesh counter-attacks lasted through the day, trying to repel the army, reports said. Fierce battles raged around the city, as troops sought to expand the route and allow aid in.

Syrian state news agency SANA said the army had made gains expanding its control near the corridor after heavy artillery and air strikes.

Syrian forces and their allies will follow the relief of Deir ez-Zor with an offensive along the Euphrates valley, the commander said.

The Euphrates valley cuts a lush, populous swathe of green about 260 km (160 miles) long and 10 km (6 miles) wide through the Syrian desert from Raqqa to the Iraqi border at al-Bukamal.

Parallel with their thrust toward Deir ez-Zor, the Syrian military and its allies have been fighting Daesh terrorists in its last pocket of ground in central Syria, near the town of al-Salamiya on the Homs-Aleppo highway.

On Wednesday, army advances gained control of four villages there, further tightening the pocket, a military media unit run by Lebanon’s Hezbollah said.

Deir al-Zor lies along the southwest bank of the Euphrates. The government enclave includes the northern half of the city and the Brigade 137 military base to the west.

The army also holds an air base and nearby streets, separated from the rest of the enclave by hundreds of meters of Daesh-held ground and still cut off from the advancing army.

Government forces will push toward the besieged airbase, the pro-Assad commander said.

Instead of breaking the siege along the main road from Palmyra, stretches of which remain in Islamic State hands, the army reached the Brigade 137 along a narrow salient from the northwest.

The corridor from the west into Brigade 137 was only about 500 meters (yards) wide, the commander said.

The United Nations has estimated that 93,000 civilians were living under Daesh siege in Deir ez-Zor in “extremely difficult” conditions, with some high-altitude air drops supplying them.

Deir ez-Zor’s provincial governor told state-run television that convoys loaded with food and medicine were on the way, along with ambulances and a mobile clinic. Residents in the enclave had gone years without vegetables, fuel, and other necessities, Mohammed Ibrahim Samra said.

“Despite all this, the schools kept running,” he said. “Our people in Deir ez-Zor have suffered a lot … and they still held on to their land.”