President Volodymyr Zelenskyy said on Sunday Ukraine needs to strengthen its air defenses to protect people after its air defense units shot down 50 of 73 Russian drones launched overnight over many regions.

"An air alert has been sounded almost daily across Ukraine this week," Zelenskyy said on Telegram messenger.

Over the past week Russia used more than 800 guided aerial bombs, about 460 attack drones, and more than 20 missiles of various types, Zelenskyy said.

"Ukraine is not a testing ground for weapons. Ukraine is a sovereign and independent state. But Russia still continues its efforts to kill our people, spread fear and panic, and weaken us," he said.

The Ukrainian military said earlier on Sunday that air defense units had destroyed more than 10 Russian drones that were targeting Kyiv in an overnight attack.

There were no immediate reports of damage or injuries as a result of the attack, Kyiv's military administration posted on Telegram.

Reuters witnesses heard explosions in Kyiv in what sounded like air defense units in operation.

"The UAVs (unmanned aerial vehicles) were flying in different directions towards Kyiv," said Serhiy Popko, head of Kyiv's military administration. "The air raid alert in the city lasted for more than three hours."

There was no immediate comment from Russia about the attack.