The International Business Times and several British newspapers are reporting that Turkey (part of the NATO alliance) shot down a Russian fighter plane over its airspace.
They report that social media users said there was a large explosion in Huraytan, northern Syria.
Last week Turkey said its jets had intercepted a Russian fighter in its airspace and the prime minister threatened to shoot down any plane that strayed in future.
Two Turkish F-16s forced the plane back into Syrian airspace on Saturday and Ahmet Davutoglu called in the Russian ambassador to protest.
He said on TV: “The Turkish armed forces have their orders. The necessary will be done even if a bird violates Turkey’s border. Rules of engagement are clear.”
Russia said the plane had entered Turkey “by mistake” and assured Ankara it would not happen again. Putin’s forces are currently supporting the Syrian regime by targeting President Bashir al-Assad’s opponents, including ISIS.
The US does not believe the violation was an error and officials held emergency talks.
Last Monday, Turkey’s military said a MIG-29 jet had harassed two Turkish F-16s for five minutes and 40 seconds on Sunday by locking its radar on to them.
The incident comes amid concerns over Russian air strikes in Syria against foreign-backed rebels.
The former chief of MI6 in England, Sir John Sawers, has warned there was a “real danger” of clashes between Russian and coalition warplanes if they mount rival operations in the skies over Syria.