Democratic presidential candidate Sen. Elizabeth Warren said she’s “very concerned about a slide towards war with Iran” and highlighted that President Donald Trump “has to come to Congress” for authorization before taking military action against Iran.

Pointing to this week’s attacks on tankers in the Gulf of Oman, the President told Fox News on Friday that “Iran did do it.”

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But Warren, the two-term progressive senator from Massachusetts who sits on the Senate Armed Services Committee, is skeptical.

“I want to see whatever evidence the administration says that it has,” she said Friday evening while campaigning in New Hampshire, the state that holds the first primary in the White House race.

“I’m very concerned about a slide towards war with Iran."

And Warren emphasized: “I want to remind this administration that the administration cannot declare war on its own. It has to come to Congress and make that case and ask for an authorization for a use of military force. That’s not politics, that’s a point of the Constitution of the United States of America.”

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The president, in a wide-ranging interview on Fox and Friends, pointed towards the attacks on the tanks and said, “we don’t take it lightly.”

“Iran did do it and you know they did it because you saw the boat,” he said, before pointing to video that showed an Iranian vessel removing an unexploded mine attached to a Japanese-owned oil tanker.

Trump said the mine had “Iran written all over it.” But he said that Iran had been damaged since he took office, but was still a threat.

"They're a nation of terror and they've changed a lot since I've been president, I can tell you,” Trump added.

Warren, a vocal Trump critic, pointed to the president’s removal of the U.S. from a nuclear treaty it and European allies signed with Tehran under President Barack Obama.

“Part of the problem we’ve got right now is that the president backed out of a deal that the United States had committed to and he does it with no coherent alternative strategy,” she noted.

And Warren argued that Trump’s been inconsistent when it comes to his positions towards Iran.

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“He’s continued to poke at Iran but then back off. At one point we hear an announcement there’s going to a huge troop buildup, then no troop buildup,” she explained. “It’s not possible to tell where the president is headed and if we can’t tell that here in the United States, it means our Congress can’t fulfill its Constitutional function. But it also means it’s hard for the Iranians to read and the rest of the world to read.”

Warren was campaigning in New Hampshire on the same day that the lineup was announced for the upcoming first round of Democratic presidential primary debates, which are coming up later this month.

Twenty of the record two-dozen candidates will make the stage for the debates – with 10 appearing on two consecutive nights, on June 26-27.

Warren is the only one of the top five polling candidates who will appear on the first night, with former Vice President Joe Biden, Sen. Bernie Sanders of Vermont, South Bend, Indiana Mayor Pete Buttigieg, and Sen. Kamala Harris all taking part in the second night’s showdown.

Warren said she wasn’t concerned, saying “there will be other opportunities” to share the debate stage with the other top polling contenders for the nomination.

“This is going to be fun,” she added.

And Warren, who’s risen in the polls the past two months, touted her retail politics metrics in New Hampshire and the other early voting primary and caucus states.

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“I’ve done more than 90 town halls, taken more than 2,000 questions, we’re crowding in on about 30,000 selfies now,” she highlighted.