Billionaire Elon Musk once again raised concerns about the possibility that the Russian invasion of Ukraine could turn into a nuclear war on Monday, this time laying out a scenario where Ukrainian efforts to take back Crimea set off a nuclear war.

On Monday, Musk retweeted an Oct. 4 Newsweek op-ed from venture capitalist David Sacks, which praised his calls for a peaceful resolution to the ongoing Russia-Ukraine conflict.

After a Twitter follower replied to Musk’s tweet to ask he still thinks there’s a possibility of a nuclear war or World War III, Musk replied with his latest scenario for a nuclear war.

“If Russia is faced with the choice of losing Crimea or using battlefield nukes, they will choose the latter. We’ve already sanctioned/cutoff Russia in every possible way, so what more do they have left to lose? If we nuke Russia back, they will nuke us and then we have WW3,” Musk tweeted.