In the latest showdown in the Syrian province of Idlib, 33 Turkish soldiers were killed, marking a culmination of several weeks of skirmishes triggered by Turkish-backed militants’ clashes with the Syrian Army.

US ambassador to NATO Kay Bailey Hutchison has called on the Turks to see "who is their reliable partner and who isn’t", urging them to ditch their contract for supplies of Russian-manufactured S-400 missile defence systems.

"I hope that President Erdogan will see that we are the ally of their past and their future and they need to drop the S-400", Hutchison told reporters in Washington, as cited by France24.

"They see what Russia is, they see what they're doing now, and if they are attacking Turkish troops, then that should outweigh everything else that is happening between Turkey and Russia", the NATO ambassador said.

The comments come as Turkish President Recep Tayyip Erdogan called an urgent meeting Thursday after 33 Turkish troops were killed in an airstrike in Syria's Idlib region. Russia's Ministry of Defence promptly commented that Russian Aerospace Forces "didn't use aviation in the area of Behun", where Turkish troops appeared to be stationed, although, according to the location updates provided by Turkey, no units of the Turkish Army were present or could be present there.

Turkey, a member state of the Western alliance, completed receiving components of Russia's S-400 missile system last year, in defiance of US warnings that the S-400s enable Russia to better track Western aircraft. In response, the US suspended Turkey's participation in the F-35 programme in July and threatened to completely evict the country from the fifth-generation stealth fighter project.

Turkey insists it will set up the S-400 in areas that are not frequented by US jets stressing it has not yet put the system into operation.

The S-400 deliveries recently came up in connection with a hike in tensions in Idlib, in Syria’s northwest, with questions arising as to whether they would continue regardless.

Turkish Foreign Minister Mevlut Cavusoglu noted earlier this month that the escalation of tensions in the Syrian province of Idlib and not seeing eye to eye with Moscow on the issue of a demilitarised zone, agreed on by the sides in 2018, will not affect the S-400 shipments to Ankara.

According to Russia's top diplomat, Sergei Lavrov, Moscow and Ankara have "very good" relations, however he conceded that total unanimity on all issues in a dialogue between any two countries is impossible. Moscow has urged Ankara to comply with existing agreements on Idlib, one of the four formally established de-escalated zones, and lamented Turkey's failure to distinguish armed opposition from terrorists.