Lviv, a city of over 700,000 roughly 70 kilometers (43 miles) east of Ukraine's border with Poland, has been largely spared from major Russian attacks in recent weeks. Two weeks ago, the Russian forces fired missiles on a military training center near Lviv, which at the time was the most westward target, and killed 35 people.

Since the beginning of the invasion, Lviv has become a safe harbor for some 200,000 displaced Ukrainians.

The explosions Saturday came as U.S. President Joe Biden was wrapping up a visit to neighboring NATO ally Poland in which he told Poland's president that `` your freedom is ours.''