On Friday, the army command said its troops took over rebel areas in the southern countryside of Idlib and the northern countryside of Hama and declared that they are free of rebels.
"Progress is continuing at a high pace," according to Syria's state news agency SANA, adding the army will continue to fight rebels across the country.
Earlier Friday, the Syrian Observatory for Human Rights, a war monitor, reported that government forces seized areas in Hama from rebels, including a town where pro-opposition Turkey has an observation post.
The breakthrough in the countryside of Hama is the first for government forces since 2012, according to the observatory.
Turkey has set up 12 observation posts in north-western Syria since a truce was reached in September between Moscow and Ankara to establish a demilitarized buffer zone in and around a key rebel enclave in Iblib.
Russia is a major military ally of Syrian President Bashar al-Assad.
The observatory said al-Assad's forces retook the town of Morek, thus completing their control of the northern countryside of Hama. Morek is home to a Turkish observation site.
"The fate of the Turkish observation point and its personnel in Morek is still unknown," observatory head Rami Abdel-Rahman told dpa.
But Turkish Foreign Minister Mevlut Cavusoglu, who is in Lebanon, denied that any Turkish soldiers in Syria are under siege.
"Let me correct your information," Ankara's top diplomat told reporters in Beirut during a joint presser with Lebanese Foreign Minister Jubran Bassil.
"There are no besieged Turkish soldiers in Syria," Cavusoglu said.
"Our observation posts in Syria are not besieged, and nobody can besiege our soldiers," he emphasized.
He also said that Turkey had no intention of leaving the areas where it has these posts.
Cavusoglu said Turkey has been working with Russia and Iran, another important supporter of al-Assad, to find a political solution to end the conflict.
Turkish President Recep Tayyip Erdogan told his Russian counterpart Vladimir Putin on Friday that the Syrian government's violations and attacks in Idlib were causing a major humanitarian crisis.
The two leaders spoke by phone for the first time after three civilians were killed and 12 wounded in an attack on a Turkish military convoy in north-western Syria this week.
Erdogan said the attacks in Idlib were damaging attempts to find a solution while also posing a serious threat to national security, state news agency Anadolu reported.
Putin will host Erdogan for a meeting in Russia on Tuesday, according to state media reports from both sides.
The meeting will take place in Moscow, Turkish state news agency Anadolu reported, citing Erdogan's office.
A ceasefire in the Idlib collapsed earlier this month.
Government forces have since recaptured around 30 towns and villages from rebels there, according to the observatory.
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