Turkey reportedly tested its Russian-made air defence system on Wednesday despite being urged by its NATO allies against the move.
Footage shared on social media that was purportedly filmed in the northern coastal town showed a white vapour trail rising into the blue sky.
The Turkish purchase of the S-400 anti-aircraft system — delivered by Russia last year at a reported cost of €2.1 billion — caused a standoff with the United States, which says the equipment could never be integrated into NATO’s air and missile defence capabilities.
Amateur video of the vapour trails over the northern town of Sinop was first shared by Turkish Minute, an opposition news outlet.
A similar report was later carried by A Haber, a broadcaster close to the Turkish government.
Turkish military and defence officials refused to comment on the reports, although a test was expected after ships and aircraft were warned to avoid the area in the Black Sea.
US officials have suspended Turkey from its F-35 fighter jet programme and previously said that Turkey risked sanctions if it ever activated the missile system.
President Recep Tayyip Erdoğan’s government has said it was force to purchase the S-400 after being denied access to US-made Patriot missiles.