BEIRUT (Reuters) - The Syrian air force bombarded a plain in the northwest of the country overnight, a group monitoring the war said, after insurgents launched an offensive to advance deeper into government-held areas vital to President Bashar al-Assad.
The insurgents are seeking to drive into the Sahl al-Ghab plain, an area crucial to the defense of the western coastal mountains that are part of the heartland of Assad's Alawite sect as well as lying close to Hama city to the southeast.
The Syrian Observatory for Human Rights, which tracks the conflict using contacts on the ground, said Syrian warplanes had carried out more than 160 air strikes on the plain and in the nearby Idlib countryside to try to disrupt the insurgents' progress towards key Assad territory.
The insurgents, who have entered at the northern tip of the plain, can use their anti-tank missiles to target Syrian army tank positions, giving them some advantages over flat ground, a diplomat tracking Syria said.
Most of Idlib province was captured earlier this year in a major advance by the insurgent grouping "Army of Conquest" against government forces.
On Tuesday, supporters of the "Army of Conquest", which is involved in the Sahl al-Ghab offensive, said fighters had seized a power station in the area and listed a total of 16 locations captured from government forces in the attack.
The military has concentrated on defending Syria's west, a tactic Assad alluded to on Sunday when he said the army had been forced to give up some areas in order to hold onto more important ones during the four-year conflict.
Insurgents involved in the current offensive under the "Army of Conquest" banner include the al Qaeda-linked Nusra Front, the Islamist Ahrar al-Sham faction and groups including Chechen and central Asian fighters, according to the Observatory.
The coastal mountain range, which acts as a buffer for government-held cities such as Latakia, is west of Sahl al-Ghab. The coastal cities, mountains and the plain itself are all home to Alawite populations.
"If the rebels take the plain then they could push all the way down and could cut off Homs and Hama," the diplomat added.
(Reporting by Sylvia Westall; Editing by Alison Williams)