"The whereabouts of 22 people are unknown - the search for them continues," President Volodymyr Zelensky announced on social media.
Two nine-story buildings in the city of Ternopil were attacked and the damage is extensive. One building has been destroyed from the third floor upwards, Ukrainian Interior Minister Ihor Klymenko announced.
A rescue operation that has been underway overnight Thursday continues.
Three of the 26 fatalities were minors. More than 90 people were injured. Ternopil residents have been advised to keep their windows closed due to health-threatening particles in the air after the large explosions.
The local authorities have declared three days of mourning in Ternopil, which before the outbreak of the great war had more than 200,000 inhabitants.
