Elon Musk has said his rocket firm SpaceX cannot continue indefinitely paying for Ukraine’s Starlink internet service in his latest spat with Kyiv.
In February, Mr Musk, the world’s richest man, activated his company’s satellite internet system in Ukraine to keep its military and people online.
But last month the Tesla owner asked the Pentagon to fund the programme instead of him, according to US media.
He recently provoked Kyiv’s ire by suggesting it cede territory.
“SpaceX is not asking to recoup past expenses, but also cannot fund the existing system indefinitely,” Mr Musk tweeted on Friday, referring to his space company that makes the Starlink system.
Starlink works by providing broadband internet through a network of satellites. It has proven vital for Ukraine’s military as it fights to retake Ukrainian land from Russia.
Ukraine credited Starlink this week with helping to reboot its infrastructure in key areas following more than 100 Russian missile strikes.
But the programme costs $20m (£18m) per month to maintain, according to Mr Musk. He recently said SpaceX has spent $80m so far to keep Ukraine online.
“In addition to terminals, we have to create, launch, maintain & replenish satellites & ground stations,” he wrote on Twitter.
“We’ve also had to defend against cyberattacks & jamming, which are getting harder.”
Ukraine’s vice-prime minister, Mykhailo Fedorov, downplayed tensions with Mr Musk, writing on Twitter that the billionaire “is among the world’s top private donors supporting Ukraine”.
“Starlink is an essential element of our critical infrastructure,” he wrote.
Earlier this month, Mr Musk tweeted out a proposal that Ukraine accept Russia’s annexation of Crimea and allow referendums in Ukrainian regions invaded by Moscow.
The Kremlin responded positively to the overture.
But Ukraine’s outgoing ambassador to Germany, Andrij Melnyk, posted a tweet telling Mr Musk to go away, using a swear word.
Responding on Friday to a post referring to the ambassador’s remark, Mr Musk said: “We’re just following his recommendation.”
Moscow has already declared four Ukrainian regions to be part of Russia, following so-called referendums denounced as fraudulent by Kyiv and its Western allies. Russia does not fully control any of the four regions.
Mr Musk has also suggested the world should “formally” recognise Crimea – illegally annexed by Moscow in 2014 – as part of Russia.
This week, Mr Musk denied that he spoke to Russian President Vladimir Putin before releasing his Twitter poll.
“I have spoken to Putin only once and that was about 18 months ago. The subject matter was space,” he tweeted.
That statement came after a think tank researcher claimed Mr Musk had personally told him about the alleged conversation.
