It said that more than 100 millimetres per square metre of rain had fallen in the affected provinces in the last 24 hours.
The provinces, home to some 2.7 million people, were hit by last month's earthquakes which killed more than 48,000 people in Türkiye and left millions homeless.
Thousands of people were staying in tents and container houses, some of which were flooded due to severe rain, after their homes were damaged by the earthquakes.