Democratic presidential candidate Bernie Sanders said Wednesday during the CNN town hall in Hew Hampshire that he wants Republican presidential candidate Donald Trump to win the GOP nomination.

Sanders criticized Trump’s claim that climate change was a hoax created by the Chinese and mockingly called him a “well-known scientist.” Sanders also tore apart Trump’s proposed tax plan. But, he said he’d like to run against the real estate mogul.

“I want Trump to win the Republican nomination,” Sanders said. “And I would love the opportunity to run against him. I think we would win by a lot.”

Trump responded on Twitter:

Sanders says he wants to run against me because he doesn’t want to run against me. He would be so easy to beat! — Donald J. Trump (@realDonaldTrump) February 4, 2016

This post has been updated.