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.

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.

Spokespeople for SpaceX, the Ukrainian government, and the Pentagon were not immediately available for comment when contacted by Fortune.

Outages

According to the Financial Times, Ukrainian troops on the front lines have been reporting outages of their Starlink-connected devices during battles that saw Ukraine’s forces push eastward in recent weeks.

The blackouts reportedly led to “catastrophic” losses of communication and panicked calls to help lines from soldiers. It was reported that the outages could have been caused by SpaceX’s efforts to stop Russian forces from misusing its technology.

Clashes with officials

The suggestion that SpaceX could stop providing Starlink at cost comes after Musk was criticized by Ukrainian officials for holding a Twitter poll on his idea for a peace deal between Ukraine and Russia—under which Crimea would be formally conceded to Russia and Moscow’s illegal annexations of four Ukrainian regions would be put to a vote.

It was later reported that Musk had spoken to Russian President Vladimir Putin before floating his peace proposals—claims that Musk vehemently denied.  

Ukraine’s President Volodymyr Zelenskyy hit back at Musk over his poll, creating his own to ask Twitter users if they preferred an Elon Musk who supported Ukraine or one who supported Russia.

Almost 2.5 million people voted, with 80% backing Ukraine. Meanwhile, Andrij Melnyk, former Ukrainian ambassador to Germany, took to the platform to tell Musk to “f*** off.”

On Friday, Musk said the U-turn on Starlink was SpaceX following Melnyk’s instruction.

Despite his recent clashes with Ukrainian officials, Musk appeared to have taken their side early on in the invasion, announcing that Starlink had been activated in Ukraine on Feb. 26—just two days after Russia launched its assault.

In early March, Starlink terminals arrived in Ukraine to help the country’s government connect to the SpaceX satellite-based internet network.

Musk later joked that he might “die under mysterious circumstances” after being condemned by a Russian official for delivering Starlink to Ukraine.

Meanwhile, a Tesla memo to its European staff in March outlined how the company was supporting the Ukrainian government, which included offering employees paid time off if they were called upon to serve in Ukraine’s military.

In a debate in Parliament this week, British lawmaker Chris Bryant questioned whether the U.K. “might have to consider sanctioning Elon Musk,” saying the Tesla cofounder “seems to be playing a double game” with Russia and Ukraine.