Dozens of Russian and Ukrainian troops, and at least eight Ukrainian civilians, were reported dead.Ukraine cut diplomatic ties with Russia, and Western countries promised harsher sanctions.

Russian forces attacked Ukraine early Thursday morning, with Ukraine reporting dozens of deaths on both sides.

Ukraine said at least 40 of its soldiers and 50 Russian troops were killed early in the fighting, according to the Associated Press and Reuters.

At least eight Ukrainian civilians were killed and nine were wounded by Russian shelling, a Ukrainian internal affairs ministry advisor said, according to Reuters.

Russia’s offensive threatens to kill thousands of people, force millions more to flee, and destabilize much of Europe, with the consequences certain to reverberate across the world.