Ukrainian President Volodymyr Zelensky on Thursday vowed a "tangible response" following a Russian missile strike on an apartment block that killed at least four people in the western city of Lviv.

"Consequences of the night attack by Russian terrorists," he wrote alongside a Telegram video post showing a ruined building. "Unfortunately, there are wounded and dead... There will definitely be a response to the enemy. A tangible one."

Russia has launched waves of drone and missile strikes across Ukraine since the February 2022 invasion.

But the Lviv region -- hundreds of kilometres from the frontlines -- has been largely peaceful. 

A Russian missile made a "direct hit to a residential building" in the city of Lviv, governor Maksym Kozytski said in a video posted to Telegram. 

The missile caused a fire which was later extinguished, he said, adding that emergency services were on the scene and rescuers were "sorting through the debris."

"As of now, the rubble is being removed. Of course, there will be injured and dead."

"We are doing everything possible to... save people."

He posted another video showing a multi-storey building with part of its top floor destroyed.  

Lviv Mayor Andriy Sadovyi said eight people were wounded in the strike and "about 60 apartments" had been damaged.

"Windows got blown out, many cars got damaged, around 50 cars... there may be more people under the rubble," he said on Telegram.

Two people had been rescued from the debris so far, he added.

Earlier, he warned that "several" missiles were "moving in the direction of the western regions," citing Ukraine's Air Forces Command.

Sadovyi earlier said on Telegram that a "series of explosions" had been heard and warned residents to stay in shelters.

One person was in "serious" condition and had been taken to hospital, he added.

Unverified videos posted to Telegram purporting to show the aftermath of the attack showed shattered glass littering the floor of what appeared to be a dormitory. 

On June 20, Lviv was hit by a major Russian drone assault on Kyiv and other cities.