Ukrainians have spent a year wondering when the next strike might come from above. Once again, they find themselves in a heightened state of alert. They fear Russian forces will mount an attack timed to the first anniversary of the war.

Civilians have lived under the constant threat of shellfire since the invasion started on February 24, 2022. They have grown used to the wail of air-raid sirens and the scramble to safety.

Officials with the United Nations High Commissioner for Human Rights say that at least 8,000 civilians have been killed in the fighting. But they say the number is likely "substantially higher." They say most of the casualties have come from artillery shells, missiles, and other weapons that cause widespread damage.

Still, Ukrainian President Volodymyr Zelenskyy said on Thursday, a day before the anniversary, that his country "will prevail."

Zelenskyy said earlier, "We will not reduce pressure on the enemy, both external and internal."

Many analysts saw Russian troops cross the border one year ago and expected Ukrainian defenses to crumble within days. However, the Ukrainians held their line and went on to reclaim territory in the east.

Russian President Vladimir Putin sent tens of thousands of soldiers into battle, followed by waves of reinforcements. British defense analysts say the Russians may have suffered as many as 200,000 casualties.

In remarks on Thursday, Russian President Vladimir Putin said, "Our troops are heroically fighting the neo-Nazism that has taken root in Ukraine, protecting our people in our historical lands and are fighting courageously and heroically."

Russian leaders have seen their Western counterparts line up to arm the Ukrainians with financial, humanitarian, and military aid. They expect their troops could soon face more advanced weapons, including battle tanks. Defence Minister Sergei Shoigu said Russians are in "grave danger."