A Syrian military commander has said Bashar al-Assad’s army will “eliminate terrorist groups” in a new ground offensive backed by Russian air strikes.

A new barrage of air strikes and cruise missiles launched by Russian naval vessels in the Caspian Sea announced the start of the operation in the Ghab plain yesterday.

Islamist groups including al-Qaeda affiliate Jabhat al-Nusra and other members of Jaysh al-Fatah (the Army of Conquest) made large territorial gains in the region in the summer, as did the Free Syrian Army and other anti-Assad rebels in the Syrian Revolutionary Command Council.

The plain is crucial for the regime’s control of western Syria and government strongholds along the coast.

General Ali Ayoub, the Syrian Arab Army’s chief of staff, said the Russian air strikes had facilitated an expanded military operation against “terrorists” - a term used by the Syrian government to refer to all armed opposition.

“The Syrian Arab armed forces began a wide-ranging attack with the aim of eliminating terrorist groups and liberating the areas and towns that suffered from their scourge and crimes,” he said in a rare television appearance.

“After the Russian air strikes, which reduced the fighting ability of Daesh (Isis) and other terrorist groups, the Arab Syrian armed forces kept the military initiative and formed armed ground troops, the most important of which is the fourth legion-raid.”

The cruise missiles hit the provinces of Raqqa and Aleppo in the north and also Idlib province in the north-west, Russian officials said.

Battles continued today, with regime forces on the ground targeting rebels in the Ghab plane region under the cover of surface-to-surface missiles and Russian air strikes from above.

Rebels are reported to have shot down at least one helicopter belonging to President Assad’s forces in Hama province in western Syria, but the claims could not be independently verified.

Isis has strongholds in Raqqa and Aleppo, while Jabhat al-Nusra and its allies have a strong presence in Idlib.

The Russian government insists it is only striking extremists but the UK-based Syrian Observatory for Human Rights said attacks by Vladimir Putin’s air force killed at least seven civilians in Idlib on Wednesday.

Previously, at least 40 civilians were reportedly killed on the first day of the Russian air strikes last week.

Syrian activists said government troops pushed out from their strongholds rural parts of Latakia province, which is the heartland of President Assad's family and Alawite minority group.

Rami Abdulrahman, founder of the Syrian Observatory for Human Rights, said troops moved from the village of Jorin into other parts of Latakia and the Ghab plain.

He said Thursday's push was along the lines of villages dominated by Alawites – who follow an offshoot of Shia Islam considered heretical by Isis and other extremist Sunni groups.

Lebanon's Al-Manar TV, which is owned by Hezbollah, the militant group fighting alongside President Assad’s troops, said the Syrian army has seized control of al-Bahsa village in Hama.

Mr Abdulrahman had recorded at least 13 regime soldiers and 11 rebels killed on the first day of the ground advance, and around 15 army tanks and armoured vehicles destroyed.

Additional reporting by Reuters and PA