No survivors of firefighting plane crash in southern Turkey
Contact was lost with the plane which had been rented from Russia to help Turkey's efforts to contain a forest fire in Kahramanmaraş, Governor Ömer Faruk Coşkun told Anadolu Agency.
A large number of search and rescue teams were dispatched to the region, added Coşkun.
The cause of the crash remains unknown.
In a separate statement, the Russian Defense Ministry confirmed the Russian Be-200 amphibious plane crashed while landing near Turkey's Adana province following a firefighting mission.
All five Russian and three Turkish servicemen on board the plane were killed in the crash, the statement said.
A special commission of the Russian Defense Ministry, as well as the employees of the Russian Embassy in Turkey, are heading to the place for the investigation, it added.
The plane was sent to Turkey on July 8 to help Turkey fight the wildfires.
Be-200 is designed specifically for fighting fires, including in remote areas, it can carry 12 tons of water.
Turkish Foreign Minister Mevlüt Çavuşoğlu said he is "deeply saddened" by the loss of the Turkish and Russian crew in the tragic plane crash.
"Their heroic sacrifices will not be forgotten!," Çavuşoğlu added.
Russian President Vladimir Putin also offered his condolences to Turkey over the loss of lives in a telegram addressing Turkish President Recep Tayyip Erdoğan.