The Syrian army on Sunday has become in full control over the main road to Deir al-Zour city in eastern Syria, after stripping the Islamic State (IS) of key areas along the road, a military source told Xinhua.

The entire road from the capital Damascus to Deir al-Zour city has become under the government control, the source said on condition of anonymity.

He added that the road had been cut off for four years.

This achievement was completed after the army took several key cities from IS on the road between the capital and Deir al-Zour city.

It started with capturing the ancient city Palmyra all the way to the key city of Sukhnah in the remote desert area in the eastern countryside of Homs province until the towns of Kabajeb and Sholah in the southern countryside of Deir al-Zour before reaching the capital city of Deir al-Zour.

The army units are now combing the road to clear it from explosives left by IS, the source said, adding that the army reached the Panorama area in the southern entrance of the capital city.

This comes as another military unit with the help of allied fighters succeeded last week to break the three-year-long siege of IS on Deir al-Zour city.

This unit stormed the siege from the western entrance of the city, marching from the southern countryside of Raqqa province until reaching the besieged Brigade 137 west of Deir al-Zour.

When the siege was lifted of the base, an adjoining enclave of government loyalists was free, where 93,000 civilians have been besieged for three years.

The primary unit kept advancing until breaking the IS siege on the air base of Deir al-Zour on Saturday.

With the advent of the troops coming from the south, which cleared the main road into the city, the IS situation is getting tough.

A day earlier, a military source told Xinhua that 90 percent of IS’ supply routes to Deir al-Zour capital city had been cut off.

Now the army will focus on defeating IS in the half of the city the IS is holding.