Editor's note: The story is being updated.
Russian forces launched two ballistic missiles against the city of Poltava on Sept. 3, killing at least 51 and injuring over 271 people, President Volodymyr Zelensky said.
The Military Institute of Communications and a neighboring medical facility were hit in the attack. The building of the educational institution was partially destroyed, according to President Volodymyr Zelensky.
"The time interval between the alarm and the arrival of the deadly missiles was so short that it caught people during an evacuation to the bomb shelter," the Defense Ministry said.
Many people remain trapped under the rubble, while rescuers and medics continue to work at the scene. As of around 2 p.m. local time, the emergency services had rescued 25 people, 11 of whom were retrieved from the rubble, according to the ministry's statement.
"We express our sincere condolences to the families of the victims. This tragedy is yet another evidence of the enemy's cunning, which stops at no crime to try to intimidate Ukrainians," the ministry said.
"We urge everyone to remain calm and trust only official sources of information. Any speculation on this tragedy is unacceptable," the ministry added.
There were no ceremonies or other events near the military institute at the time of the Russian attack, Dmytro Lazutkin, Defense Ministry spokesperson, said on national television, refuting such unofficial claims.
According to the Defense Ministry, students were studying, and then followed to the shelter after an air raid alert went off, Lazutkin added.
Zelensky said he had instructed an operational investigation into the circumstances of the attack on Poltava. Ukraine's Ground Forces is conducting an investigation to determine "whether enough was done to protect the lives and health of the soldiers at the facility," the military said.
Poltava is a city of around 300,000, located in Poltava Oblast in central Ukraine. The city is situated around 120 kilometers (75 miles) from the border with Russia, and 230 kilometers (143 miles) from the eastern front.
The city and surrounding region are regular targets of Russian drone and missile attacks.