DAMASCUS, Syria — Russian warships in the Caspian Sea fired cruise missiles as Syrian government troops launched a ground offensive Wednesday in central Syria, in the first major combined air-and-ground assault since Moscow began its military campaign in the country last week.

The missiles, launched from a Russian flotilla in the Caspian Sea, travelled 1,400 kilometers (900 miles) over “unpopulated areas” to target militants, according to a Russian officer.

The latest developments — exactly a week after Russia began launching airstrikes in Syria — add a new layer to the fray in the complex war that has torn this Mideast country apart since 2011.

Moscow has mainly targeted central and northwestern Syria, strategic regions that are the gateway to President Bashar Assad’s strongholds in Damascus, and along the Mediterranean coast. But the strikes appear to have given Assad new confidence to try to retake some lost ground.

According to the Syrian official, the government push is concentrated in the adjacent provinces of Hama and Idlib where rebels have been advancing in the past months. The official spoke on condition of anonymity in line with regulations.

The Islamic State group is not present in the areas where the fighting is underway.

Wednesday’s offensive in central Syria and the ensuing clashes with militants, including al-Qaida’s Syrian branch, was the first major ground fighting since Moscow began launching air raids in Syria last week.

The Russian airstrikes appear to have emboldened Syrian troops to launch the ground push after suffering a string of setbacks in northwestern Syria over the past few months.

In Moscow, Russian Defense Minister Sergei Shoigu said Russia is using warships in the Caspian Sea to target the Islamic State group in Syria. Shoigu told President Vladimir Putin in televised remarks that Russia on Wednesday morning carried out 26 missile strikes from four warships of its Caspian Sea flotilla. Shoigu insisted the operation destroyed all the targets and did not launch any strikes upon civilian areas.

Andrei Kartapolov of the Russian General Staff told Russian news agencies that Russia had planned the missile strikes from the warships so that they would be flying “over unpopulated areas.” Shoigu also said Russia has carried out 112 airstrikes on IS positions since its operation began on Sept. 30.

The Britain-based Syrian Observatory for Human Rights said a government offensive began on four fronts early Wednesday in the northwestern provinces of Idlib and neighboring Hama. Observatory director Rami Abdurrahman described it as “the most intense fighting in months.”

In Syria, the leader of a U.S.-backed rebel group, Tajammu Alezzah confirmed the ground offensive in a text message to the media, claiming there were Russian and Iranian soldiers in the operation.