Russia has begun carrying out air strikes in Syria against opponents of President Bashar al-Assad, Moscow has confirmed.
The strikes reportedly hit the rebel-controlled area of Hama province.
Washington was informed an hour before that they were about to take place.
Russian defence officials say the strikes targeted the the Islamic State group, but an unnamed US official told Reuters that so far they did not appear to be targeting IS-held territory.
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 latest developments came amid reports that President Assad had formally requested Russian military support.
Reports from Russia say the upper house of the Russian parliament granted President Vladimir Putin permission to deploy the Russian air force in Syria.
The Russian defence ministry said the country’s air force had targeted IS military equipment, communication facilities, arms depots, ammunition and fuel supplies.
A Syrian opposition activist network, the Local Co-ordination Committees, said Russian warplanes hit five towns – Zafaraneh, Rastan, Talbiseh, Makarmia and Ghanto – resulting in the deaths of 36 people, including five children.
None of the areas targeted were controlled by IS, activists said.
A US defence official said: “A Russian official in Baghdad this morning informed US embassy personnel that Russian military aircraft would begin flying anti-Isil [IS] missions today over Syria. He further requested that US aircraft avoid Syrian airspace during these missions.”
Later, US state department spokesman John Kirby told reporters: “The US-led coalition will continue to fly missions over Iraq and Syria as planned and in support of our international mission to degrade and destroy Isil [IS].”
Syria’s civil war
What’s the human cost?
More than 250,000 Syrians have been killed and a million injured in four-and-a-half years of armed conflict, which began with anti-government protests before escalating into a full-scale civil war.
And the survivors?
More than 11 million others have been forced from their homes, four million of them abroad, as forces loyal to President Assad and those opposed to his rule battle each other – as well as jihadist militants from IS and other groups. Growing numbers of refugees are going to Europe.
How has the world reacted?
Regional and world powers have also been drawn into the conflict. Iran and Russia, along with Lebanon’s Hezbollah movement, are propping up the Alawite-led government. Turkey, Saudi Arabia and Qatar are backing the Sunni-dominated opposition, along with the US, UK and France.
Diplomatic goals behind Putin’s Syria build-up
Migrant crisis: Fleeing life under Islamic State in Syria
Are you in the area? Have you been affected? You can share your experience by emailing.
Please include a contact number if you are willing to speak to a BBC journalist. You can also contact us in the following ways:
- Whatsapp: +44 7525 900971
- Send pictures/video to
- Upload your pictures / video here
- Tweet: @BBC_HaveYourSay
- Send an SMS or MMS to +44 7624 800 100