At least three Russian missiles have attacked an aircraft repair plant in the western Ukrainian city of Lviv, located 50 miles from the Polish border, and serves as a haven for hundreds of thousands of internally displaced Ukrainians.

At least three explosions were heard shortly after 6 a.m. on Friday, preceded by the sound of air-raid sirens and the appearance of a mushroom-shaped column of smoke rising into the sky.

Andriy Sadovy, the mayor of Lviv, said the civilian airport had been spared damage and that authorities were examining the situation and would provide updates.

According to Agence France-Presse, emergency crews rushed to the area while motorists were turned away at checkpoints.

Lviv, a Unesco world heritage site, had remained primarily unaffected by bombings until Friday, though many of the city's 700,000 residents believed an attack was imminent.

According to some, the city represents Ukraine's essence and a symbol of Ukrainian nationalism. Its residents were among the most vocal in favor of the country's independence from the Soviet Union.

Lviv has been converted into a garrison town since the Russian invasion began. It is the epicenter of the country's nationalist movement, and inhabitants were well aware that the city, with its public airport and military airfield, would have been in Russia's crosshairs.

Foreign embassies have been relocated to Lviv in reaction to Russia's assault on Kyiv, with the city becoming the new diplomatic capital of Ukraine and the focal point of the western response.

Thousands of displaced individuals seeking shelter at the train station arrive daily from eastern communities destroyed by bombs. At least 200,000 internally displaced persons live in Lviv, straining the city's capacity.