Tech tycoon Elon Musk joined a call between US President-elect Donald Trump and Ukrainian President Volodymyr Zelensky the day after the presidential election, according to a source with knowledge of the situation.

Zelensky previously said on X that he called Trump on Wednesday and congratulated him on “his historic landslide” win. “We agreed to maintain close dialogue and advance our cooperation. Strong and unwavering US leadership is vital for the world and for a just peace,” Zelensky wrote at the time.

Trump’s victory comes at a precarious moment in the conflict for Kyiv as Russia makes gains in the eastern Donbas region, which Russian President Vladimir Putin aims to capture in full.

Throughout his presidential campaign, Trump cast doubt on continued US commitment to Kyiv as the war drags on more than two and half years after Russian forces invaded. He has also made comments that suggest the US could pressure Ukraine into an uneasy truce with Russia.

Musk – whose pro-Trump super PAC spent more than $118 million in the 2024 campaign – has pitched himself to lead a broad effort to slash spending inside the federal government. His inclusion on Trump’s call with Zelensky raises questions about what his influence will look like in the incoming administration.

In Ukraine, Musk’s Starlink internet service has provided a significant frontline advantage to Ukraine’s smaller military since the 2022 invasion, permitting its forces to share real-time drone feeds between units, and communicate in areas where combat has disrupted cellphone service.

But there have also been concerns about Musk’s reported links with hostile foreign leaders.

A September Wall Street Journal report said the SpaceX founder and Russian President Vladimir Putin have been in “regular contact” since late 2022, saying they had discussed “personal topics, business and geopolitical tensions.”

It raised national security concerns as SpaceX’s relationships with NASA and the US military may have granted Musk access to sensitive government information and US intelligence.

Musk did not respond to the Journal’s requests for comment. Kremlin spokesman Dmitry Peskov told the newspaper that Musk and Putin have only had one telephone call in which they discussed “space as well as current and future technologies.”

This is a developing story and will be updated.