The row between Elon Musk, the world's richest man, and U.S. President Donald Trump was triggered by stress on both sides and Elon made a mistake by publicly challenging Trump, Musk's father told Russian media in Moscow.

In an interview with NBC News, the president also said he assumes his relationship with the tech billionaire is over after their recent falling-out.

"They've been under incredible stress for five months, give them a break," Errol Musk said while attending a forum by Putin's ultranationalist ally in Moscow.