WASHINGTON -- US tech billionaire Elon Musk and Secretary of State Marco Rubio on Sunday had an online clash with Poland's foreign minister over Starlink use in Ukraine.

Musk, chief executive officer of the aerospace company SpaceX, wrote on social platform X that "my Starlink system is the backbone of the Ukrainian army," and "Their entire front line would collapse if I turned it off."

In response, Polish Foreign Minister Radoslaw Sikorski wrote on X that Starlinks for Ukraine are paid for by the Polish Digitization Ministry at the cost of about 50 million US dollars per year.

"The ethics of threatening the victim of aggression apart, if SpaceX proves to be an unreliable provider we will be forced to look for other suppliers," he said.

Rubio accused the Polish minister of "just making things up".

"No one has made any threats about cutting Ukraine off from Starlink. And say thank you because without Starlink Ukraine would have lost this war long ago and Russians would be on the border with Poland right now," he added.

Musk then explained: "I am simply stating that, without Starlink, the Ukrainian lines would collapse, as the Russians can jam all other communications! We would never do such a thing or use it as a bargaining chip."

Starlink has been widely used by Ukrainian forces during its conflict with Russia. US negotiators have reportedly threatened to cut off Ukraine's access to Starlink if an agreement on the country's critical minerals and other resources cannot be reached.

The Trump administration had announced a suspension of weapon deliveries to Ukraine and halted intelligence sharing after a heated Oval Office meeting with Ukrainian President Volodymyr Zelensky more than a week ago.