The Ukrainian military beefed up defenses against Russian assaults in the east and south on Sunday, as the country’s president framed the conflict as an existential threat to European democracy as a whole.

“Russia is a target for the entire European project,” President Volodymyr Zelensky said in a video address, calling the conflict in Ukraine a “catastrophe” that will “inevitably” spread elsewhere in Europe.

“Russian aggression was not intended to be limited to Ukraine alone, to the annihilation of our freedom and lives alone,” he continued.

The Ukrainian military said it was resisting Russian attempts to break through in the east from the city of Izyum, which Russian forces have used as a strategic foothold to take more territory. Ukraine said it was still fighting Russian attacks in Mariupol, a southeastern port city that has been largely destroyed by weeks of street fighting and shelling.

Ukraine has been bracing for new Russian advances in the south and east since Russian troops pulled back from Kyiv earlier this month after failing to take the capital and becoming stranded in the city’s northern reaches. Russia claims to be concentrating its efforts in the eastern Donbas region, which is home to two breakaway pro-Russia republics where fighting has raged since 2014.

Maxar Technologies released satellite images on Sunday that appear to show an eight-mile-long convoy of Russian military vehicles heading south about 60 miles east of Kharkiv. According to US officials, Russia has appointed a new commander to oversee its invasion of Ukraine, signaling yet another shift in strategy.

In recent weeks, Western military analysts have downplayed Russia’s military prowess, describing its troops as demoralized and diminished by a surprising stiff resistance from volunteer defenders and a Ukraine army armed with NATO-supplied technology and weapons.

“Russia will likely continue to throw badly damaged and partially reconstituted units piecemeal into offensive operations that make limited gains at great cost.” the Washington-based Institute for the Study of War predicted in a new report. It cited recent intelligence from Western military officials that Russia’s armed forces have begun re-enlisting retired soldiers to compensate for mounting casualties, indicating Russia’s desperation.

According to the think tank, Russia may be able to secure much of the Donbas region if it can “trap or wear down Ukrainian forces,” but Russian forces may be depleted before that happens.

Ukrainian authorities have urged civilians to flee the east and parts of the south in recent days, citing an impending Russian offensive.

However, there has been considerable unease in the aftermath of a missile strike on a train station in the eastern city of Kramatorsk on Friday, which killed at least 52 people and injured more than 100 others. Civilians fleeing the Donbass clogged the station.

Those responsible for the railway strike would be apprehended and charged with war crimes, Zelensky promised. Following the discovery of civilian murders north of Kyiv, Ukraine’s president made a similar promise.

Following a meeting with British Prime Minister Boris Johnson on Saturday, Zelensky’s rhetoric soared to Churchillian heights. Two weeks ago, armored columns of Russian tanks were poised at the city’s northern reaches, and the two leaders took a stroll through downtown Kyiv, an outing that would have been unthinkable.

Johnson was the most recent in a long line of high-ranking European officials to travel to Kiev. More are expected in the coming days as European leaders seek to demonstrate solidarity with Ukraine and its president, whose global popularity has skyrocketed since the conflict began.

Following Johnson’s visit, the United Kingdom announced that it would send 120 armored vehicles and anti-shipping missile systems to Ukraine. Russia has bombarded Ukraine with missiles from land and sea, most notably in Mariupol, which has been battered for months.

The threat appeared to have receded a few weeks later, with Russia withdrawing some of its forces and refocusing its attention to the east. Residents took to the streets on a sunny Sunday, strolling through the city’s elegant parks and boulevards.