Turkey restricted access to social media websites for several hours after the Islamic State group released a video purportedly showing two Turkish soldiers being burned alive.
The video came as Turkish warplanes on Friday pounded the extremist-held town in Syria near where the soldiers are believed to have gone missing.
IS released the video late on Thursday, which purports to show the killing of two soldiers captured near the northern Syrian town of al-Bab last month. Syrian activists said the soldiers went missing in the area of al-Dana, northwest of al-Bab, in late November.
Turkish Defense Minister Fikri Isik would not confirm the authenticity of the video.
"Up to now, we have information that three of our soldiers are in the hands of Daesh," Isik said, using an Arabic acronym for the IS group. "All other statements are not (based on) information that has not been confirmed."
Turkey Blocks, an internet monitoring website, said it had detected the "throttling of Twitter and YouTube", affecting many users in Turkey. Turkey frequently restricts access to social media websites to prevent the spread of graphic images and other material authorities say would harm public order or security. The websites appeared to be back to normal on Friday.
Police meanwhile rounded up 31 suspected IS militants in Istanbul and were searching for 10 others wanted by prosecutors investigating the extremist group, the state-run Anadolu Agency reported.
Turkish warplanes have meanwhile carried out air strikes over the past three days on al-Bab, killing dozens of people.
The IS-run Aamaq news agency said a Friday air strike on al-Bab killed at least 20 people, and released a video showing infants among the dead being pulled from the debris.
The Britain-based Syrian Observatory for Human Rights said Friday's air strike killed 16 people, including three children. It said 88 people have been killed by air strikes over the past three days.
On Friday, President Recep Tayyip Erdogan declared that the Turkish-supported offensive to recapture al-Bab was on the verge of completion, without providing further information.
