US media reported that President-elect Donald Trump involved billionaire Elon Musk in a phone call between him and Ukrainian President Volodymyr Zelensky, who called to congratulate Trump on his victory in the US presidential elections last Tuesday.

CNN quoted a source as saying that Musk was with Trump at his private resort, Mar-a-Lago, in Florida, when Zelensky called to congratulate the president-elect in a "positive and friendly" conversation.

The source added that Trump turned on the speakerphone to include Musk in the call, and the Ukrainian president thanked the billionaire - who heads a number of the largest technology companies - for his help in providing communications services to Ukraine via the Starlink system during the ongoing war with Russia.

The source said that the call lasted about 7 minutes and did not address political issues.

CNN reported that Musk's participation in the call, which he supported with millions of dollars in Trump's campaign, raises questions about the limits of his expected influence in the next US administration.

The network also noted that Trump, during his election campaign, raised doubts about continued US support for Ukraine if he won the presidency and made statements indicating the possibility of pushing Kiev to reach a truce with Russia.

In turn, the Associated Press quoted a Ukrainian official familiar with the call as saying that Zelensky and Musk spoke during the call that took place last Wednesday, but he said that Musk may not have been on the line during the entire call, apparently.

The agency said Musk's involvement in the conversation shows his influence in the president's inner circle. It noted that Trump had talked about the possibility of assigning Musk to an official role in the next administration concerned with government efficiency, which raises questions about a conflict of interest in light of the large government contracts that Musk leads SpaceX.