Starlink systems used by Ukrainian military units were down for two and a half hours overnight, a senior commander said, part of a global issue that disrupted the satellite internet provider.
Ukraine's forces are heavily reliant on thousands of SpaceX's Starlink terminals for battlefield communications and some drone operations, as they have proved resistant to espionage and signal jamming throughout the three and a half years of fighting Russia's invasion.
Starlink experienced one of its biggest international outages on Thursday when an internal software failure knocked tens of thousands of users offline.
"Starlink is down across the entire front," Robert Brovdi, the commander of Ukraine's drone forces, wrote on Telegram at 10:41 p.m. (1941 GMT) on Thursday.
He updated his post later to say that by about 1:05 a.m. on Friday the issue had been resolved. He said the incident had highlighted the risk of reliance on the systems, and called for communication and connectivity methods to be diversified.
"Combat missions were performed without a (video) feed, battlefield reconnaissance was done with strike (drones)," Brovdi wrote.
Oleksandr Dmitriev, the founder of OCHI, a Ukrainian system that centralizes feeds from thousands of drone crews across the frontline, told Reuters the outage showed that relying on cloud services to command units and relay battlefield drone reconnaissance was a "huge risk".
"If connection to the internet is lost ... the ability to conduct combat operations is practically gone," he said, calling for a move towards local communication systems that are not reliant on the internet.
Although Starlink does not operate in Russia, Ukrainian officials have said that Moscow's troops are also widely using the systems on the frontlines in Ukraine.