Fierce fighting raged in Latakia province on Syria's coastline on Sunday, as the army pushed an advance and killed a jihadist leader, a monitoring group said.
The regime deployed massive reinforcements to fight rebels in Latakia, which has strategic and symbolic significance because it is the ancestral home of President Bashar al-Assad's clan.
Rebels positioned in remote enclaves of Latakia's mountains launched the "battle for the liberation of the Syrian coast" about two weeks ago.
Poorly equipped local fighters allied themselves with the jihadist Islamic State of Iraq and the Levant (ISIS), despite a history of poor relations.
Rami Abdel Rahman of the Syrian Observatory for Human Rights said the army sent "massive reinforcements" to Latakia to fight the rebels and "bombed rebel areas heavily".
State television said the army has reclaimed rebel positions in the province, including Kharata, Janzuriyeh, Baluta, Baruda and Hambushiyeh.
But according to Abdel Rahman, "the army has only been able to secure the outskirts of some villages. The battles are ongoing and they are fierce".
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"Scores of foreign (jihadist) fighters are being killed in the Latakia fighting," he told AFP.
Among them was a Libyan emir or local leader of ISIS, said the Observatory.
"Confirmed reports emerged of the killing of a Libyan ISIS emir while fighting in Jamusiyeh village," said the Britain-based monitoring group.
The Syrian air force also struck several rebel positions across the country, it added.
Among its targets were the Jabal al-Arbaeen area of the northwestern province of Idlib, Daraya and Zabadani near Damascus, and Deir Ezzor city in the east of Syria and a rebel area nearby.
It also struck a rebel area in Homs province, said the Observatory.
Syria's war has killed more than 100,000 people in 29 months, according to the United Nations.
On Saturday alone, at least 124 people were killed across Syria, the Observatory reported.