Ukraine's president has said his nation will not respond to provocations amid a deadly escalation in fighting in rebel Russian-backed eastern territories, BBC reports.
But Volodymyr Zelensky told world leaders Ukraine would defend itself against Russian aggression.
Two Ukrainian soldiers were killed on a third day of clashes between Ukraine's military and Russian-backed rebels.
US President Joe Biden said he was convinced Russia would invade Ukraine, but Moscow has denied this.
Western nations have accused Russia of trying to stage a fake crisis in the eastern regions as a pretext to invade.
But speaking to a security conference in Munich, President Zelensky said Ukrainians were "not panicking, we want to live our lives".
He accused Western leaders of a "policy of appeasement" towards Moscow and demanded Ukraine be given new security guarantees. President Zelensky travelled to Munich despite being warned by US officials that it was unsafe to leave his country.
His comments came as monitors reported a "dramatic increase" in attacks along the line dividing rebel and government forces in eastern Ukraine. There were more than 1,400 explosions in the breakaway Donetsk and Luhansk regions on Saturday alone, monitors said.
Denys Monastyrsky, the Ukrainian interior minister, had to be hurried into a bomb shelter after coming under shellfire while he was touring the front lines.
Rebels in the self-declared people's republics of Donetsk and Luhansk have ordered a mobilisation of all men of fighting age and urged other civilians to evacuate to Russia. The separatists claimed, without providing evidence, that Ukraine was planning to attack.
Many did not comply with the evacuation order, instead remaining at their homes.
Russian media released a series of unverified reports of attacks or attempted attacks inside rebel-held territory on Saturday.
Russia launched a criminal investigation into reports, denied by Ukraine, that shells exploded on Russian territory in the Rostov region, about 1km (0.6 mile) from the Ukrainian border.
As reports of shelling continued, Germany and France became the latest Western countries to urge their citizens to leave Ukraine. The German airliner Lufthansa will suspend flights to Ukraine for a week from Monday.
