Gwynne Shotwell, president and chief operating officer of SpaceX, said on Wednesday the Starlink service - which has provided Ukraine with broadband communications in its defence against Russian forces - was "never meant to be weaponized."
Mykhailo Podolyak, a political adviser to Ukrainian President Volodymyr Zelenskiy, criticised the decision on Twitter, another of billionaire Musk's companies.
"A year of Ukrainian resistance & companies have to decide: Either they are on the side of Ukraine & the right to freedom, and don't seek ways to do harm. Or they are on Russia's side & its 'right' to kill & seize territories," Podolyak wrote.
"SpaceX (Starlink) & Mrs. Shotwell should choose a specific option," he said.
Ukraine's military uses thousands of Starlink devices to communicate in the field. Some of the devices were provided by the company free of charge.
Despite the importance of Starlink for Kyiv, Podolyak has criticised Musk more than once since the Russian invasion of Ukraine.
He has dismissed ideas put forward by Musk for "exchang(ing) foreign territories for an illusory peace", and urged him not to "pessimize" Ukrainian official accounts of the conflict.
(Reporting by Max Hunder, Editing by Timothy Heritage and Chizu Nomiyama)