The Trump administration escalated its sudden saber rattling toward Iran when President Donald Trump directly criticized Tehran in a series of tweets Wednesday night and Thursday morning.

Hours after his top national security adviser put Iran “on notice” and other senior administration officials refused to rule out U.S. military action against the Islamic Republic, Trump himself appeared to threaten the Middle Eastern power in a series of tweets — and the words of U.S. presidents carry far more weight than career bureaucrats briefing behind the veil of anonymity.

The president used his personal Twitter account to say around 6:30 a.m. Thursday that Iran has been “formally PUT ON NOTICE for firing a ballistic missile,” using all capital letters to likely add weight to his words. Iranian leaders “should have been thankful for the terrible deal the U.S. made with them!” he continued.

Iran has been formally PUT ON NOTICE for firing a ballistic missile.Should have been thankful for the terrible deal the U.S. made with them!

— Donald J. Trump (@realDonaldTrump) February 2, 2017

Trump followed that tweet with one that took a shot at the Obama administration and other global powers who inked a deal with Iran in 2015 over its nuclear arms program, a pact that included easing sanctions and releasing frozen Iranian assets.

The new U.S. commander in chief wrote that Iran was on its “last legs” before the nuclear deal and argued thatWashington gave it a $150 billion “lifeline” via the deal.

Iran was on its last legs and ready to collapse until the U.S. came along and gave it a life-line in the form of the Iran Deal: $150 billion

— Donald J. Trump (@realDonaldTrump) February 2, 2017

PolitiFact, an independent fact-checking project operated by the Tampa Bay Times, examined similar claims Trump made during the presidential campaign. “Experts say $150 billion is the high end of estimates,” PolitiFact wrote last March. “Most peg the the total value of Iranian assets at around $100 billion, but Iran probably still won’t be able to access all of it.”

The president’s Thursday morning posts came about nine hours after Trump first joined his administration’s seemingly out-of-the-blue attacks on Iranian behavior. Late Wednesday night, he said Iran has been seizing larger and larger swaths of Iraq while previous U.S. administrations “squandered three trillion dollars there.”

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The Trump administration clearly wants to turn up the heat on Iranian leaders, but just how far the new president is willing to go to force Tehran to alter its behavior is unclear. Senior administration officials declined to answer multiple questions about Trump’s willingness to use U.S. military force during a Wednesday background briefing that at times felt like the beginning of a confrontation with Iran.

The officials, who briefed reporters at the White House on condition of anonymity to be candid, said the U.S. has a “large range of options available … from financial and economic … to pursuing other options related to support for those that are challenging and opposing Iranian malign activity in the region.”

Asked multiple times whether that list of options includes military force, three senior administration officials repeatedly declined to state that Trump, for now at least, is not exploring deploying the U.S. military against Iran.

“We are considering a whole range of options. We’re in a deliberative process. The important thing here is that we are communicating that Iranian behavior needs to be rethought by Tehran,” one of the senior officials said.

“We consider these actions to be inherently destabilizing and a threat to our friends and our allies, and as counterproductive to the goals of the region,” the official told reporters. “It undermines the people’s security in the region, and creates inherent instability.”

The official then delivered the second hawkish threat of the day toward Iran from the White House podium in as many hours: “That is something that Tehran needs to consider and think through because we are considering these things in a different perspective.”

Ordinarily, when a White House goes out of its way to deliver muscular threats, but refuses to clearly state that the military option is off the table, the implication is that military force is very much on a president’s list of options.

About two hours before the officials spoke to reporters on Wednesday, the president dispatched his national security adviser, Michael Flynn, to the White House briefing room to call out Iran for its support of Houthi forces in Yemen that have struck Emirati and Saudi ships, and for its recent ballistic missile test.

“In these and other similar activities, Iran continues to threaten U.S. friends and allies in the region,” said Flynn, a retired three-star general who was fired by the Obama administration. “As of today, we are officially putting Iran on notice.”

Asked to elaborate on Flynn’s hawkish warning, one of the senior administration officials responded, “I’m not going to address that.”

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The officials revealed that the new administration has kicked off a “deliberative process” to review and finalize its Iran policy. For that reason, the officials acknowledged they were unable to say that military options have been ruled out.

“You’re asking for the results of a review process that is just now beginning. We’ve been here for a few days,” one of the officials said. “These are questions to which the answers are ….” he then stammered a bit before saying, “We don’t have anything to say for reasons that will not surprise you.”

But the afternoon’s “on notice” warning followed by the officials’ refusal to rule out military action signaled that the Trump administration will likely take a hard line against Iran. But the new White House’s message is as vague as it is hawkish, leaving open the possibility that Iranian leaders could misinterpret it and act out.

Asked whether the Trump administration has attempted to avoid some sort of incident by dispatching a third party or even by talking directly to the Iranian government, one of the officials only added to a confusing afternoon at the executive mansion by responding, “I don’t think we would comment on that today.”