Syria claims shooting down of US drone over Latakia
The Syrian military says it has shot down a US drone near the city of Latakia, a stronghold of President Bashar al-Assad in north-west Syria.
US officials have said they lost contact with a drone but that it is unclear if it was shot down.
If confirmed it would be the first time Syrian forces have attacked a US aircraft since the start of coalition strikes against Islamic State (IS).
Syria has not been participating in the raids on IS.
The country's state-run Sana news agency described the unmanned surveillance plane as "hostile", without giving further details. The Pentagon said it was looking into the incident.
In a BBC interview last month, President Assad said "general messages" were provided to the Syrians about the coalition strikes via a third party.
A Jordanian jet involved in the coalition strikes crashed in northern Syria last year. IS captured the pilot and later burned him alive.
Analysis - Jim Muir, BBC News, Beirut
The apparent shooting-down of an American drone comes at an odd time, when US and UN officials have said that President Assad has to be engaged in a negotiated settlement of the Syrian crisis.
The US and Syria also find themselves on the same side of the fence in confronting the militants of IS in Syria, and Syrian air defence systems have been "passive" since American and other coalition jets began bombarding IS positions in September.
But the downed drone was flying over the coastal heartland of the Alawites, the powerful Shia sect to which the Assad family belongs. There is no opposition or IS presence in the area, but a heavy deployment of regime forces.
So the shooting-down of the drone - assuming it did not simply crash - would carry the same message as when Syrian defences brought down a Turkish jet in June 2012 : that Syria is not a soft touch, and is ready to defend its airspace against hostile intruders.
Meanwhile, Syrian activists have accused government forces of using chlorine in an attack in the north-western province of Idlib late on Monday.
Two groups reported that three children were among six people killed when aircraft dropped barrel bombs filled with the toxic chemical on Sarmin.
The Syrian military has denied the claim, describing it as propaganda.
Chlorine is a common industrial chemical, but its use as a weapon is banned by the Chemical Weapons Convention (CWC).
Syria signed the treaty after the nerve agent sarin was used in an August 2013 attack on several suburbs of Damascus that killed hundreds of people. Western powers said only the government could have carried out the attack, but it blamed the rebels.
In January, international investigators concluded that chlorine gas had been used in air raids on three villages that were blamed on the government.
Earlier this month, the UN Security Council approved a resolution that condemned the use of toxic chemicals such as chlorine in Syria, and threatened military action in case of further violations.