Elon Musk said he is willing to sell Tesla stock if the United Nations can prove that $6 billion would solve the hunger crisis, after the director of a UN program said a small percentage of the billionaire's wealth could help alleviate the emergency, The Hill reported.

David Beasley, director of the UN’s World Food Program (WFP), told CNN in an interview that billionaires must “step up now, on a one-time basis” to help fund the effort to combat world hunger.

“Six billion to help 42 million people that are literally going to die if we don't reach them. It's not complicated,” he said, pointing to Musk and Amazon founder Jeff Bezos, the world's two richest men.

Musk responded to Beasley’s comments in a tweet, challenging the WFP to describe in a Twitter thread “exactly how” $6 billion could help solve world hunger. If successful, Musk said he would sell Tesla stock “right now and do it.”

He added, "But it must be open source accounting, so the public sees precisely how the money is spent."

Beasley responded to Musk in the Twitter thread, inviting the billionaire to review the program’s systems for transparency and work with them.