Top Turkish airline companies canceled flights to Iranian cities on Friday amid protests against the rising cost of living.
A countrywide internet blackout was reported in Iran on Thursday and extended into Friday as authorities moved to curb expanding protests.
Nationwide demonstrations over economic hardships started at the end of December, and have shaken the country.
Turkish Airlines said it was canceling 17 flights scheduled for Friday and Saturday to the Iranian cities of Tehran, Tabriz and Mashhad.
The carrier had already canceled two flights to Tehran on Thursday and one to Tabriz, a spokesperson told Agence France-Presse (AFP).
According to the specialist website Flight Radar, a Turkish Airlines plane flying to Shiraz and a budget carrier Pegasus flight to Mashhad turned back from Iranian space on Thursday night.
Turkish budget carrier Ajet announced it canceled six flights scheduled for Friday and Saturday to Tehran.
Pegasus Airlines also canceled flights to Iranian cities on Friday, the Turkish media reported.
According to the Istanbul Airport app, five other flights operated by Iranian airlines had also been canceled.
The Iranian government was already battling an economic crisis after years of sanctions and recovering from the June war against Israel.
Rights groups have accused Iranian security forces of opening fire on demonstrators, with the Norway-based NGO Iran Human Rights saying Thursday that security forces had killed at least 45 protesters, including eight minors, since the demonstrations began.
Türkiye shares a border of around 500 kilometres (300 miles) with Iran, and there are three active land crossings between the two countries.
