Fierce clashes between rebels and fighters loyal to President Bashar al-Assad's regime raged on Thursday around insurgent-held Qusayr in central Syria, a monitoring group said.
An army officer told AFP the military seized control of Shumariyeh village near the town of Qusayr.
"The Syrian army seized back control of Shumariyeh in the Qusayr countryside, and troops are currently on their way to the village of Ghassaniyeh" which has been under rebel control for more than a year, the officer said.
The Syrian Observatory for Human Rights confirmed the claim.
"Backed by pro-regime militia and Hezbollah fighters, the army is advancing in the Qusayr area," Observatory director Rami Abdel Rahman told AFP.
"They have superior firepower and their campaign to take back Qusayr is fierce," he added.
Backed by fighters loyal to powerful Lebanese Shiite movement Hezbollah, which supports Assad, the Damascus regime launched an intensified bid last month to retake Qusayr.
The town fell out of regime control more than a year ago, but has faced daily shelling and frequent aerial bombardment.
It is strategically located near the Lebanese border and just south of Syria's third city, Homs, which lies on the road linking Damascus to the coast.
Rebels battling to topple Assad's regime have long claimed that Hezbollah was involved in Syria's fighting.
The movement's chief Hassan Nasrallah acknowledged last week that members of the group were fighting inside Syria.
He also suggested that key Assad backer Iran and other states could intervene to support the Damascus regime against rebels.
Nasrallah is scheduled to deliver a speech later on Thursday.
Lebanon has suffered a spillover of Syria's raging conflict, with frequent cross-border shelling targeting the north and the east of the small Mediterranean country.
On Thursday, three shells hit Hermel in eastern Lebanon, and two others hit Masharia al-Qaa nearby, a security source told AFP on condition of anonymity.
Fighting also raged in flashpoints across Syria, among them Barzeh in northern Damascus, said the Observatory, which relies on a broad network of activists, doctors and lawyers for its reports.
More than 70,000 people have died in the Syrian conflict, the United Nations says.