The UK-based Syrian Observatory for Human Rights (SOHR) said on Saturday that the Syrian army had taken the town of al-Sukhna from the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) as government troops advanced towards ISIL strongholds in the east of the country.
Al-Sukhna lies some 50km away from the neighboring Deir Az Zor region, which is almost entirely under ISIL control.
The town lies along a highway that would allow Syrian government forces to push into ISIL territory.
Earlier on Saturday, the monitor reported clashes between government troops and ISIL fighters while the army "advanced slowly" inside the city.
There was no official confirmation from the Syrian government regarding the capture, but Syrian state news agency SANA said earlier that the army was moving into al-Sukhna from three directions.
Battle for Raqqa
ISIL is losing ground fast in Syria to separate campaigns waged by the Russian-backed Syrian government on the one hand, and to US-backed Kurdish forces and their allies on the other.
Government forces have also been advancing against ISIL in Hama province and in southern areas of Raqqa province.
US-led operations against ISIL are currently focused on taking the city of Raqqa in northern Syria.
The Syrian Democratic Forces (SDF), a Kurdish-led fighting coalition backed by US-led coalition air raids, has made steady advances from the eastern and western side of Raqqa.
The SDF began its assault on the ISIL stronghold on June 6.
On Friday, a senior US official said that there were about 2,000 ISIL fighters who remained in Raqqa.
"Today in Raqqa, ISIS is fighting for every last block ... and fighting for their own survival," Brett McGurk, US special envoy for the coalition against ISIL, told reporters.
Last week, the US-led coalition said 45 percent of Raqqa was under control of the SDF.
The United Nations said late last month that more than 200,000 people have fled their homes in the area around the city.
It also said that an estimated 20,000 to 50,000 civilians remained in Raqqa.