"Our air forces took part in the coalition forces' air operations in Mosul," Yildirim told his ruling Justice and Development Party (AKP) parliamentary group in Ankara.
The long-awaited offensive began yesterday with air and ground support from a US-led coalition. Yildirim said Turkey was "closely-watching" what was happening but did not give details on the nature of the Turkish air support.
Yildirim repeated President Recep Tayyip Erdogan's comments from Monday that Turkey would be involved in the operation and will be "at the table".
Yildirim told his MPs that Turkey continuously cautioned the United States and the European Union about the region's sensitivities.
"We frequently warned about the ethnic sensitivities of the region and indicated the sectarian sensitivities," Yildirim said.
Earlier this month, Erdogan and Iraqi Prime Minister Haider al-Abadi traded barbs over Turkey's presence in Bashiqa in northern Iraq, where according to Erdogan nearly 700 Turkish soldiers are based.
Turkey denies Baghdad's claims that it is an "occupying force", insisting that it is providing training for fighters whom the Turkish government says will assist Peshmerga forces retake Mosul.