Türkiye's National Intelligence Organization (MIT) chief Ibrahim Kalın visited Syria's capital Damascus on Thursday.
Kalın prayed at the historic Umayyad Mosque, amid heavy security measures, according to video footage.
He is expected to hold meetings with Syria's anti-regime commander Ahmed al-Sharaa, better known as Abu Mohammed al-Golani and Syria's new interim prime minister Mohammed al-Bashir.
The Syrian information ministry said there would be talks involving its new anti-regime leadership.
The ministry said that Kalın and Qatar's head of state security, Khalfan al-Kaabi, arrived in the capital to meet with Syrian anti-regime leader Ahmed al-Sharaa and caretaker prime minister Mohammad al-Bashir.
Türkiye's Foreign Ministry denied the Syrian ministry's additional notice that Foreign Minister Hakan Fidan was also in Damascus for talks, saying he remained in Türkiye.
Fidan attended events in Ankara on Thursday including the arrival of Hungarian Prime Minister Viktor Orban, and is to meet Secretary of State Antony Blinken in Ankara on Friday.
Doha did not immediately confirm that Kaabi had arrived.
Kalın's visit would be the first by a senior foreign official to Damascus since the anti-regime forces toppled Bashar Assad on Sunday, ending his family's 50-year rule in a swift takeover after 13 years of civil war.
The Türkiye's National Intelligence Organization (MIT) did not immediately comment on the visit.
