Syrian government forces have launched an attack to capture a rebel-held hill in northwestern Syria, a rebel official and the Syrian Observatory for Human Rights reported, an expansion of operations that have continued in that area despite a deal to cease fighting.
Rebels said the assault on Kabani hill in the province of Latakia was supported by Russian air strikes.
Both the government and rebels have accused each other of violating the truce, which came into effect on Saturday. The agreement does not include Islamic State or the Nusra Front, an al Qaeda-linked group that has a wide presence in northwestern Syria.
The hill overlooks the rebel-held town of Jisr al-Shughour in neighbouring Idlib province, and the Ghab Plain, where rebel advances last year were seen as a growing threat to President Bashar al-Assad.
"The regime and militias are trying to storm (the hill) under very fierce Russian air cover and artillery fire," said Fadi Ahmad, spokesman for the First Coastal Division, a group fighting under the banner of the Free Syrian Army.
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Rami Abdulrahman, Observatory director, said: "If the regime is able to capture Kabani hill, the insurgents will be in a difficult position because this hill overlooks the Ghab Plain and Jisr al-Shughour."
A rebel commander in northern Syria said: "Battles continue in vital areas that the regime wants, and where there was no truce in the first place. There is bombardment and battles."
"We are in the fifth day and there is no change in these areas," he said, in reference to areas in the provinces of Latakia, Homs and Hama.
