Washington (CNN) President Donald Trump's amped up rhetoric that the US is "locked and loaded" sparked new fears of war with Iran but also confusion about his true intentions following an attack on a Saudi oil field that rocked global oil markets.

The Trump administration upgraded the incident into a global crisis with its swift move to directly blame Iran for the coordinated drone strike. The strike was claimed by Houthi rebels that Tehran supports in Yemen.

The President's comments sparked immediate uncertainty over whether he was being serious or whether this tension-raising tweet was -- like a similar warning once aimed at North Korea -- a risky negotiating tactic.

It is unclear whether his "locked and loaded" phraseology threatens military force against Iran, its proxies in Iraq or Yemen or some kind of US response that stops short of retaliatory attacks.

In fresh sign of the administration's incoherent messaging on a war-or-peace issue, Vice President Mike Pence's chief of staff Marc Short appeared to try to draw the US back from the brink on Monday morning.

"I think that 'locked and loaded' is a broad term and talks about the realities that we're all far safer and more secure domestically from energy independence," he told reporters.

But Trump's aggressive response already has raised the possibility that the US could become embroiled in a military confrontation between two bitter regional rivals that could quickly spin out of control.

The latest developments also underscore that even without recently departed Iran hawk John Bolton in the White House, the path of US Iran policy perpetually courts the risk of a dangerous escalation.

They also highlight the head-spinning nature of Trump's foreign policy. The President had recently seemed to be trying to set up a meeting with Iranian President Hassan Rouhani as he goes in pursuit of big wins abroad to boost his reelection bid. Now, he's apparently threatening war.

"There is reason to believe that we know the culprit, are locked and loaded depending on verification, but are waiting to hear from the Kingdom as to who they believe was the cause of this attack, and under what terms we would proceed!" Trump tweeted on Sunday.

Confusion about Trump's intentions at a time of flaring tensions with Iran was compounded by another of his tweets on Monday morning that appeared to downplay the effect of the oil refinery attack on US interests.

"We are a net Energy Exporter, & now the Number One Energy Producer in the World. We don't need Middle Eastern Oil & Gas, & in fact have very few tankers there, but will help our Allies!"

That tweet bolstered a growing impression that US foreign policy at any moment depends on Trump's whiplash mood reflected by his often contradictory tweets, a culture of inconsistency that US adversaries may now be exploiting.

On Sunday, for instance, Trump claimed reports that he had agreed to meet Rouhani with "no conditions" was incorrect. But Treasury Secretary Steven Mnuchin said Thursday the President "has said he would sit down with Rouhani with no conditions."

Risks of war

If he was intending to rattle Iran but not signal military action, Trump's brinkmanship will spark fresh fears that his hyper personal approach could inadvertently drag the US into a conflict that could quickly escalate with unpredictable, damaging consequences in the Middle East and beyond.

US officials Sunday pointed to satellite imagery provided to CNN showing the oil facilities were struck from the northwest, suggesting an attack from Iraq, where Tehran has proxies or Iran, among other information. Tehran has denied any involvement.

But if the attack was the work of Iran there will be speculation that Tehran has concluded that the President's previous unwillingness to back up his rhetoric with military force during a previous confrontation in July and the departure of Bolton, means Washington is unlikely to respond to any provocation.

That would set up a classic scenario whereby misunderstood signals and careless escalations can drag two adversaries into a conflict neither really wants.

The implication meanwhile that the President was awaiting a go ahead from Saudi Arabia also opened him up to accusations he was outsourcing US military action to a foreign power.

It also highlighted how his hardline anti-Iran policy has put all US chips on Saudi Crown Prince Mohammed bin Salman who is seen by many Washington foreign policy experts as aggressive and unpredictable and presiding over an ill-advised war in Yemen that has ignited a devastating humanitarian crisis.

So far, the United States, for all its tough talk, has not provided any proof that Iran was directly behind an attack whose sophistication raised suspicions it was beyond the Houthis.

Given the President's propensity to peddle untruths, the burden of truth for any military strike would be high -- even higher than it would have been given that inaccurate intelligence led the US into its last major war in the Middle East, in Iraq.

Questions about Iran's calculations

Secretary of State Mike Pompeo first raised the stakes over the strike at the Saudi oil facility on Saturday.

"Tehran is behind nearly 100 attacks on Saudi Arabia while Rouhani and Zarif pretend to engage in diplomacy. Amid all the calls for de-escalation, Iran has now launched an unprecedented attack on the world's energy supply. There is no evidence the attacks came from Yemen," Pompeo wrote.

His unequivocal declaration all but boxed the United States into a strong response to the attack, possibly involving some kind of military action.

Yet it also begs the question whether the President is fully on board with his own secretary of state who is now wielding even more power over US foreign policy with Bolton gone.

Trump said he decided in June to pull back a military strike against Iran at the last moment because it would have killed many civilians and was not proportionate to avenge the downing of a US drone over the Gulf of Oman by the Islamic Republic.

There were subsequent reports that he complained that his aides were trying to goad him into a war with Iran that could contradict his campaign vow to avoid new Middle East entanglement.

If Iran or an Iranian proxy does turn out to be behind an attack that sent global oil prices soaring, there will be questions about the Islamic Republic's motivation and how it is calculating its response to Trump's policies.

The developments could suggest Iran has no intention of responding to any US overtures, following Trump's decision to pull out of the nuclear deal forged by his predecessor Barack Obama and the adoption of a "maximum pressure" sanctions campaign.

Iranian politics are notoriously difficult to judge from the outside. But the crisis could also indicate that factions in the Islamic Republic are seeking to squelch any political maneuvering room for any leaders who are open to talking to the US.

Rouhani did not specifically reference the attack on the Saudi facility in an address on Iran's Press TV Sunday but did accuse Americans of running a "war operation" by supporting the UAE and Saudi Arabia.

On Monday, an Iranian Foreign Ministry spokesman said that a meeting between Trump and Rouhani at the UN General Assembly in New York next week was not on the agenda but didn't directly rule it out.

Recent developments would seem to close Trump's latitude for a meeting. But the President cares little for convention and would love to spring a surprise.