At least four people were killed and dozens of homes were destroyed after a Russian missile strike in Ukraine’s Lviv city, the Kyiv administration said on Thursday, New York Times reported.

According to officials, this is the biggest attack on the western Ukrainian city since the crisis began more than 16 months ago. The authorities said the ages of the victims ranged from 21-95 and also warned that some people might still be trapped under the rubbles.

In addition to this, more than 30 people were wounded in the pre-dawn strike in Lviv. The city is hundreds of miles from the front lines and has largely been spared the worst violence of the war, NYT reported.

Reacting to the missile attack, Ukrainian President Volodymyr Zelenskyy vowed a response and said that it would be a “strong one.”

“Lviv. Consequences of the night attack by Russian terrorists. Unfortunately, there are wounded and dead. My condolences to the relatives! There will definitely be a response to the enemy. A strong one,” Zelenskyy said on Twitter.

The Ukrainian military said that Russian forces fired 10 Kalibr cruise missiles from carriers and submarines in the Black Sea, out of which seven missiles were intercepted, while the other hit the apartment complex and other sites.

Maksym Kozytskyy, the head of the regional military administration, said that a piece of critical infrastructure had also been damaged but did not provide details, NYT reported.

“This is the largest attack on Lviv’s civilian infrastructure since the beginning of the full-scale invasion. There are dead and wounded. More than 50 apartments were destroyed,” Andriy Sadovyi, the city’s mayor, said in a video posted on Twitter.

Air-raid alerts had started wailing at about 1:30 am (local time) in parts of Ukraine — including in the capital, Kyiv — before spreading to other regions. An hour later, the whole country was marked “red” on online alert maps, with Ukraine’s Air Force warning that several missiles were moving toward the west, NYT reported.

“It was very loud,” Mr Kozytskyy, the head of the regional administration, wrote on the Telegram app just before 3 am (local time), urging people to stay in a safe place.