Ukraine’s president has made an impassioned plea to Western allies to speed arms deliveries and help stem “terrifying” casualties as Russian forces lay siege to the eastern city of Severodonetsk, destroying the last bridges into the industrial hub.

The cities of Severodonetsk and Lysychansk have been targeted for weeks as the last areas in the eastern Donbas region of Lugansk still under Ukrainian control.

President Volodymyr Zelensky said Monday the human cost of the battle for the region was “simply terrifying.”

Zelensky expressed confidence in Ukraine’s ability to reclaim territory, calling on the nation’s allies to send more weapons.

“We just need enough weapons to ensure all of this. Our partners have them.”

With the screws tightening on the Lugansk region, Ukrainian forces have two choices: “to surrender or die,” said Eduard Basurin, a representative for pro-Russian separatists.

The capture of Severodonetsk would open the road to Sloviansk and another major city, Kramatorsk, in Moscow’s push to conquer Donbas, a mainly Russian-speaking region partly held by pro-Kremlin separatists since 2014.