Drew Angerer via Getty Images President Donald Trump threatened to "totally destroy North Korea" to defend the U.S. or its allies in his address before the U.N. General Assembly on Sept. 19.

President Donald Trump’s increasingly tense relationship with Pyongyang has rattled members of Congress to such a degree that three Democratic senators announced a bill on Wednesday that would prohibit Trump from striking North Korea ― with nuclear or conventional weapons ― without obtaining congressional approval first.

Sen. Chis Murphy (D-Conn.) tweeted a series of messages about the proposed legislation, which he is introducing with Sens. Brian Schatz (D-Hawaii) and Cory Booker (D-N.J.).

″My bill ... makes clear that any unauthorized preemptive strike on N Korea - nuclear or conventional - is illegal,” Murphy wrote.

Trump's North Korea threats are real. I will intro bill w @brianschatz & @CoryBooker to prohibit any preemptive action w/o vote by Congress. — Chris Murphy (@ChrisMurphyCT) October 26, 2017

My bill w @brianschatz & @CoryBooker makes clear that any unauthorized preemptive strike on N Korea - nuclear or conventional - is illegal. — Chris Murphy (@ChrisMurphyCT) October 26, 2017

Mistake by Trump could kill hundreds of thousands on Korean Peninsula. My bill w @brianschatz @CoryBooker will clarify Trump's war powers. — Chris Murphy (@ChrisMurphyCT) October 26, 2017

For all the Republicans breaking w Trump, here is your chance to actually constrain his most dangerous power - to make war. — Chris Murphy (@ChrisMurphyCT) October 26, 2017

The bill follows legislation reintroduced by Rep. Ted Lieu (D-Calif.) and Sen. Ed Markey (D-Mass.) in January that would limit the president’s ability to launch a first nuclear strike without a declaration of war from Congress.

“Trump’s North Korea threats are real,” Murphy wrote. “Mistake by Trump could kill hundreds of thousands on Korean Peninsula.”

The war of words between Pyongyang and Washington has continued to heat up in recent months, ahead of Trump’s visit to South Korea in November.

Earlier this month, North Korea’s deputy ambassador to the United Nations, Kim In Ryong, warned the U.N. General Assembly’s disarmament committee that a nuclear war “may break out at any moment.” While such bluster is relatively normal for the country, equally destructive rhetoric from the White House has begun to rattle those at home and abroad.

Trump in September threatened to “totally destroy” North Korea and mocked leader Kim Jong Un as a “rocket man” on Twitter.

Earlier this week, Japan’s Defense Minister Itsunori Onodera told the U.S. and South Korea that the North Korean threat had grown to a “critical and imminent level,” according to Reuters, and he called on his counterparts to help rein in the antagonistic nation.

White House officials have kept the possibility of diplomacy open, even as the United Nations has imposted harsh sanctions on North Korea. Secretary of State Rex Tillerson said earlier this month that America would be willing to negotiate with Pyongyang “until the first bomb drops.”

Trump is set to travel to South Korea on Nov. 7 as part of his trip across Asia, where he will “celebrate the enduring alliance and friendship” between Washington and Seoul. It’s unclear if Trump will visit the Korean Demilitarized Zone on his trip and scowl northward, as Vice President Mike Pence did earlier this year.

Bloomberg via Getty Images Vice President Mike Pence looks across to the north side of the border at the truce village of Panmunjom in the Demilitarized Zone (DMZ) in Paju, South Korea, in April.