President Trump claimed Sunday that his tweets are sufficient notice to Congress of any possible U.S. military strike on Iran, in an apparent dismissal of his obligations under the War Powers Act of 1973.

Trump’s declaration, which comes two days after his administration launched a drone strike that killed top Iranian military commander Qasem Soleimani, was met with disbelief and ridicule from congressional Democrats, who called on the president to respect the role of the legislative branch in authorizing new military action abroad.

“These Media Posts will serve as notification to the United States Congress that should Iran strike any U.S. person or target, the United States will quickly & fully strike back, & perhaps in a disproportionate manner,” Trump tweeted from his Mar-a-Lago Club in Palm Beach, Fla., late Sunday afternoon. “Such legal notice is not required, but is given nevertheless!”

Trump’s claim that the United States will retaliate against Iran “perhaps in a disproportionate manner” also contrasts with Secretary of State Mike Pompeo’s statement hours earlier on “Fox News Sunday” that the administration “will take responses that are appropriate and commensurate with actions that threaten American lives.”

The War Powers Act of 1973 mandates that the president report to lawmakers within 48 hours of introducing military forces into armed conflict abroad. Such notifications generally detail an administration’s justification for U.S. intervention, as well as the constitutional and legislative rationale used by the administration to send troops. It may also include how long the involvement could last.

On Saturday, the White House delivered a formal notification to Congress of the strike that killed Soleimani, according to a senior Democratic aide and another official familiar with the matter who spoke on the condition of anonymity ahead of the notification.

But the document, which is entirely classified, drew scathing criticism from House Speaker Nancy Pelosi (D-Calif.), who said in a statement that the notification “raises more questions than it answers.”

Several congressional Democrats sharply criticized the president on Sunday afternoon for appearing to dismiss the War Powers Act.

“OMG, Trump thinks a crazed Tweet satisfies his War Powers Act obligations to Congress,” Rep. Jared Huffman (D-Calif.) tweeted. “Our President has taken us to the brink of war and is now vamping with no plan and no clue. Please, someone in the GOP, take the car keys - read the 25th Amendment.”

The 25th Amendment outlines a procedure by which the Cabinet can remove a president from office.

Rep. Mark Pocan (D-Wis.) also pushed back against Trump’s declaration.

“.@realDonaldTrump, this is Twitter,” Pocan tweeted. “This is not where you wage unauthorized wars.”

Sen. Bernie Sanders (I-Vt.), who is running for the Democratic presidential nomination, called on members of Congress to unite against Trump’s efforts to potentially take further military action against Iran.

“Congress must reassert its constitutional responsibility over war,” Sanders said in a tweet. “The Senate and House must vote to immediately defund unauthorized military action against Iran.”

Trump’s Sunday social media post does not mark the first time he has sought to craft policy by tweet.

In June 2017, he announced on Twitter that he would ban transgender people from serving in the military in any capacity.

“After consultation with my Generals and military experts, please be advised that the United States Government will not accept or allow transgender individuals to serve in any capacity in the U.S. Military,” Trump wrote at the time.

Trump has also announced the hiring and firing of a number of administration officials via Twitter.

Seung Min Kim contributed to this report.