A video released by the "Islamic State" (IS) shows what appears to be two Turkish soldiers who lost contact with their squad last month being burned alive. Turkey restricted internet access after the video's release.
The graphic video released late on Thursday reportedly shows two uniformed soldiers being hauled from a cage, chained up and then set on fire.
Speaking Turkish, the killer denounces Turkish President Recep Tayyip Erdogan and calls for "destruction to be sowed" in Turkey.
The footage was supposedly shot in the IS-declared "Aleppo Province" in northern Syria, where the Turkish military has been engaged in a months-long incursion against the jihadi group.
The 19-minute video has yet to be independently verified and Turkish officials refused to comment. However, the IS news agency Amaq announced last month that militants had kidnapped two Turkish troops, while Turkey had separately said that it had lost contact with two soldiers fighting in Syria. The men give their names in the video, although it remains unclear whether they are the same as those of the missing soldiers.
The video was then published online and distributed across social media. In the wake of its release, Turkish authorities throttled popular content sharing websites, such as Facebook and YouTube. It is commonplace for the government to restrict access to social media during times unrest, claiming that graphic content risks harming public order and security.
The latest video recalls the shocking killing of Jordanian fighter pilot Maaz al-Kassasbe, who was captured by IS militants in December 2014 after his plane went down. He was later burned alive in his cage.
Turkey suffers heavy losses in Al-Bab
The video's release comes a day after Turkish forces suffered their heaviest losses yet during their incursion into Syria.
Sixteen Turkish troops were killed by IS insurgents Wednesday around the Syrian town of Al-Bab, located just 30 kilometers (18 miles) from the southern Turkish border.
Turkey's offensive into al-Bab continued into Friday, with the Syrian Observatory for Human Rights reporting that at least 88 civilians have been killed in airstrikes.
Turkey's incursion into Syria began on August 24, with Ankara seeking to support allied rebel groups and oust both IS and Kurdish militia forces from its border area with Syria.
Discussing Wednesday's death toll, Erdogan pledged to push ahead with the incursion. "Yes, maybe we will have to lay martyrs to rest," he said. "But we are determined to preserve their memory and protect what they left us and continue this struggle."
Turkey's defense minister, Fikri Isik, told parliament on Thursday that military forces had so far "neutralized" 1,005 IS members and 299 fighters affiliated with the Kurdish Peoples' Protection Units (YPG).
While Ankara considers the YPG a terror group, the Kurdish group has also been fighting alongside US forces in the war against IS.
Turkey meanwhile has suffered 38 casualties. However, with almost half of all casualties incurring in a single day, Turkey potentially faces a long, bloody incursion in its quest to seize al-Bab.
dm/sms (AFP, Reuters, dpa)