(WASHINGTON) -- President Joe Biden on Friday defended ordering the U.S. military, in coordination with the United Kingdom and other partners, to carry out large-scale retaliatory strikes in Yemen against Iran-backed Houthi militants over their attacks on shipping in the Red Sea.
Speaking with reporters Friday afternoon on a trip to Pennsylvania, he called the strikes a "success" and said the U.S. will continue to respond if the Houthis keep up their "outrageous behavior."
The Houthis have vowed revenge.
Asked for his message to Iran, Biden said, "I already delivered the message to Iran. They know not to do anything."
When asked if the U.S. was in a de facto war with Iran, he said no. “Iran does not want a war with us.”
The strikes, intended to weaken the militants' ability to continue targeting commercial vessels in the vital waterway, were being met with mixed reaction on Capitol Hill -- even criticism from some Democrats in an election year when foreign policy can become a major issue.
Earlier, National Security Council spokesman John Kirby said the administration is "not interested in a war with Yemen."
"We're not interested in a conflict of any kind here," he told reporters aboard Air Force One. "In fact, everything the president has been doing has been trying to prevent any escalation of conflict, including the strikes last night."
Some lawmakers, like Senate Republican leader Mitch McConnell and House Speaker Mike Johnson, welcomed the action as necessary but overdue.
"The United States and our allies must leave no room to doubt that the days of unanswered terrorist aggression are over," McConnell said.
Others, including progressive Democrats and hard-line Republicans, are slamming Biden for acting alone without approval from Congress.
"This is an unacceptable violation of the Constitution," Rep. Pramila Jayapal, the chair of the Congressional Progressive Caucus, wrote in a social media post. "Article 1 requires that military action be authorized by Congress."
Kirby was asked by a reporter about the bipartisan group of lawmakers who contend Biden violated the War Powers resolution.
"We're very comfortable and confident in the legal authorities that the president exercised to conduct these strikes," he responded.
President Biden labeled the strikes as a "defensive action" taken in light of the 27 attacks initiated by Houthi militants in the Red Sea since November, which he said impacted more than 50 nations.
Tensions are high in the Middle East in the aftermath of Hamas' deadly attack in Israel in October, with fears that the violence in Gaza could spread beyond its border and into other parts of the region.
Houthi military spokesman Brig. Gen. Yahya Saree said the strikes "will not go unanswered and unpunished" and that they will continue targeting ships in the Red Sea they say are heading toward Israel's ports. Yemen, Iran and Hamas also condemned the U.S.-led strikes.
More political reaction
Leaders of key congressional committees on the subject signaled their approval of Biden's action.
"This strike was two months overdue, but it is a good first step toward restoring deterrence in the Red Sea," said. Republican Roger Wicker, the ranking member of the Senate Armed Services Committee. "I appreciate that the administration took the advice of our regional commanders and targeted critical nodes within Houthi-controlled Yemeni territory."
Senate Foreign Relations Committee chairman Ben Cardin, a Maryland Democrat, said he supported Biden's "decision to take precise action against these increasingly dangerous provocations that have threatened the interests of the U.S. and our allies, and welcome our coalition partners taking these actions with us."
"I look forward to continued consultation with the Administration on this decision, as required by law, and encourage the President to persist in his efforts to keep this conflict from spreading further in the region," he said.
But there is a sizable amount of bipartisan pushback and criticism of the president's handling of the situation.
"This is illegal and violates Article I of the Constitution," said Missouri Democrat Cori Bush. "The people do not want more of our taxpayer dollars going to endless war and the killing of civilians. Stop the bombing and do better by us."
California Democrat Ro Khanna, a Biden campaign surrogate, also said Biden should've come to Congress and that his action was "unconstitutional."
"I think this has increased the risk of retaliation against our embassies and retaliation against our troops," Khanna said on CNN. "And that's why I don't understand how they did not come to Congress. How did the White House have the time to talk to the Canadians, the British, the Australians but not to members of Congress?"
Several conservatives echoed that message.
"He can't unilaterally pull us into another war. Why does he want so many wars?" said Arizona Republican Rep. Andy Biggs. Georgia Republican Marjorie Taylor Greene, one of Biden's loudest critics, said "Biden can not solely decide to bomb Yemen."
"This is where we should put party aside and stand for the oath we all took: Congress alone decides if we go to war," said South Carolina Republican Nancy Mace. "I join my colleagues on both sides insisting we follow the Constitution."
Former President Donald Trump, the GOP frontrunner to face Biden in a potential rematch, criticized Biden in a Truth Social post.
"So, let me get this straight. We're dropping bombs all over the Middle East, AGAIN (where I defeated ISIS!), and our Secretary of Defence, who just went missing for five days, is running the war from his laptop in a hospital room," Trump said, referring to Secretary Lloyd Austin's recent secretive hospitalization revealed to be for complications resulting from prostate cancer treatment.
"Remember, this is the same gang that 'surrendered' in Afghanistan, where no one was held accountable or FIRED," Trump continued. "It was the most embarrassing 'moment' in the history of the United States. Now we have wars in Ukraine, Israel, and Yemen, but no 'war' on our Southern Border. Oh, that makes a lot of sense."
Earlier this week, ahead of the strikes, other Republican presidential hopefuls criticized Biden as being too slow to respond to the Houthi attacks in the Red Sea during a primary debate.
Former U.N. Ambassador Nikki Haley contended Biden had been " hiding in a corner" on the issue, and Florida Gov. Ron DeSantis accused Biden of "leaving [U.S. service members] out to dry."
ABC News' Fritz Farrow contributed to this report.