Syria's former al-Qaeda affiliate claimed responsibility for the downing of a Russian warplane in northern Syria, apparently using a surface-to-air missile.
The pilot was killed after he ejected and exchanged gunfire with militants on the ground, the Russian Defence Ministry and a monitoring group said.
Hayat Tahrir al-Sham, or HTS, a powerful rebel alliance that publicly split from al-Qaeda last year, said it had used a man-portable anti-aircraft system to shoot down the Su-25 fighter jet as it flew low over the opposition-held town of Saraqeb. That claim was echoed by Russia's Interfax news agency, quoting the Defence Ministry, as well as the Britain-based Syrian Observatory for Human Rights.
The incident could raise tensions between Russia and Turkey, which is monitoring a so-called "de-escalation zone" in the northern province of Idlib as part of an agreement made during Syrian peace talks in the Kazakh capital, Astana.
It also raises questions about the source of the apparent Manpads, a weapon for which Syria's rebels have repeatedly pleaded from their international backers. The US in particular has been strongly opposed, fearing that anti-aircraft weapons could fall into the hands of the country's extremist groups. "The US has never provided Manpad missiles to any group in Syria, and we are deeply concerned that such weapons are being used," State Department spokeswoman Heather Nauert said.