Sen. Jeff Flake, R-Ariz., called President Trump’s public boast that he too has a “nuclear button" that’s “bigger” and “more powerful” than North Korea’s troublesome.

“This is disturbing on so many levels,” Flake tweeted in response to Trump’s tweet.

Trump’s tweet was prompted by North Korean leader Kim Jong Un’s claim Monday that the U.S. should know he has a nuclear button device readily available on his desk.

“North Korean Leader Kim Jong Un just stated that the ‘Nuclear Button is on his desk at all times,’” Trump tweeted Tuesday evening in response. “Will someone from his depleted and food starved regime please inform him that I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!”

North Korea ramped up its nuclear weapons and missile programs in 2017, Trump's first year in office, despite international pressure and sanctions designed to convince Pyongyang to stop.

The Trump administration has said it has not ruled out a military option for handling North Korea, but stressed it would rather take a diplomatic route.