Elon Musk has said it is “unreasonable” to expect SpaceX to provide its Starlink internet service in Ukraine indefinitely amid reports the company asked the Pentagon to foot the half-a-billion-dollar bill instead.

Starlink—a division of Musk’s SpaceX that uses satellites to provide high-speed internet—has played a vital role in the war, enabling the Ukrainian government to maintain communications channels even as Russian forces have destroyed phone and internet infrastructure.

Thousands of Starlink terminals are now operational in Ukraine, having been donated by SpaceX or paid for by the U.S. government or crowdfunding initiatives.

However, CNN reported on Thursday night that SpaceX had sent a letter to the Pentagon saying it could no longer fund Starlink in Ukraine to the same degree.

The letter asked the Pentagon to take over the funding, which SpaceX said would cost more than $120 million for the rest of the year and almost $400 million over the next 12 months.

Documents seen by CNN also showed that Ukraine’s top military commander had asked for around 8,000 more Starlink terminals in July, which a SpaceX consultant said in a separate letter meant the company was being faced with “terribly difficult decisions.”

“I do not think they have the ability to provide any additional terminals or service as requested,” they wrote.

Musk appeared to confirm CNN’s report on Friday, saying in a tweet that SpaceX was not asking to recoup past expenses but could not “fund the existing system indefinitely and send several thousand more terminals that have data usage up to 100X greater than typical households.”

“This is unreasonable,” he said.

In a later tweet, Musk said the provision of Starlink in Ukraine was creating a number of challenges alongside losses that were nearing an eye-watering $20 million a month.

https://twitter.com/elonmusk/status/1580811694225653760

Earlier this month, Musk revealed that SpaceX’s Ukrainian Starlink operation had cost the company $80 million, with the costs set to exceed $100 million by the end of the year. He said only a small percentage of the Starlink terminals and services had been paid for.