Russia has begun carrying out air strikes in Syria against opponents of President Bashar al-Assad.

The strikes reportedly hit rebel-controlled areas of Homs and Hama provinces, causing casualties. The US says it was informed an hour before they took place.

The Russian Defence Ministry said it had carried out about 20 flights over Syria, hitting eight Islamic State targets.

The ministry said Russian jets had destroyed an Islamic State command post and an operations centres in a mountainous area, Russian agencies reported.

The strikes did not hit civilian infrastructure or areas nearby, the ministry said.

The ministry said the country’s air force had targeted IS military equipment, communication facilities, arms depots, ammunition and fuel supplies.

US officials said targets in the Homs area appeared to have been struck, but not areas held by Islamic State.

Syria’s civil war has raged for four years, with an array of armed groups fighting to overthrow the government.

The US and its allies have insisted that President Assad should leave office, while Russia has backed its ally remaining in power.

The upper house of the Russian parliament earlier granted President Vladimir Putin permission to deploy the Russian air force in Syria.