US Secretary of State Mike Pompeo on Thursday said Iran had "engaged in an escalating series of threatening actions and statements in recent weeks" and that "any attacks by them or their proxies against US interests or citizens will be answered with a swift and decisive US response."
"Iran’s 40 years of killing American soldiers, attacking American facilities and taking American hostages is a constant reminder that we must defend ourselves," Mr Pompeo said, again stressing that the US did not seek war.
He urged Tehran to seek "a path to a prosperous future through de-escalation to modify the regime’s behaviour".
US National Security Adviser John Bolton convened a meeting at CIA headquarters last week with the Trump administration's top intelligence, diplomatic and military advisers to discuss Iran, NBC reported on Thursday.
The meeting was on April 29, before a US aircraft carrier and bombers were sent to the region after intelligence identified possible Iranian plots against US interests and troops in the region.
The Trump administration is seeking diplomatic engagement with Tehran to try to negotiate a new nuclear deal and address Iran’s regional policies, even as the US increases economic and military pressure.
"What I’d like to see with Iran, I’d like to see them call me," US President Donald Trump said on Thursday, in his second call for direct engagement with Iran in less than 24 hours.
“I look forward to some day meeting with the leaders of Iran to work out an agreement and, very importantly, taking steps to give Iran the future it deserves,” he said on Wednesday.
That same day he announced new US sanctions on Iran's steel, aluminium and copper exports.
The president’s aide on the Middle East, Victoria Coates, said Mr Trump’s offer to talk was sincere and “it is his hope that they will accept”.
The US aircraft carrier Abraham Lincoln crossed the Suez Canal on its way to the Gulf waters on Thursday.
Behnam Ben Taleblu, a senior fellow at the Foundation for Defence of Democracies, said that by increasing its presence the US was trying to deter Tehran and use “coercive diplomacy to bring Iran back to the table”.
"Washington's hardening of its military assets in the region course-corrects from a period in 2018 where there were zero carriers in the Gulf region," Mr Ben Taleblu told The National.
The strategy was used by the Bush and Obama administrations and led to nuclear talks in Geneva in 2008, and a secret back channel mediated by Oman in 2011.
Those efforts culminated, under Mr Obama, in the nuclear deal of 2015.
"I would not be surprised to see some diplomatic engagement between the Trump administration and Tehran,” said Suzanne Maloney, deputy director of the foreign policy programme at the Brookings Institution.
“That is the preferred outcome for the president himself and it's clear from [Iranian] Foreign Minister Javad Zarif's recent round of US outreach that Tehran is prepared to test the waters, if only in a very preliminary fashion, to see if dialogue could assuage Trump's appetite for economic pressure."
But Ms Maloney was dubious about the chances of such engagement bringing about a tenable breakthrough on the 12 demands that Secretary of State Mike Pompeo laid out for Iran last year.
They include Tehran curbing its aggressive regional stance and domestic repression.
“The mutual mistrust and animosity is simply too high and I see no evidence that this administration is committed to devising a real framework for sustained, complex negotiations,” Ms Maloney said.
Last September, Mr Trump and Iranian President Hassan Rouhani were close to meeting on the sidelines of the UN General Assembly.
Aaron Miller of the Woodrow Wilson Centre said a meeting between the two “would fall in the category of a summit of the vanities”.
The US president “loves high-visibility, centre-stage displays”, Mr Miller said, but the better path would be for back-channel talks on decreasing the risk of conflict, to begin with.
But this is at odds with the direction National Security Adviser John Bolton and Mr Pompeo are taking, Mr Miller said.
Iran's policymakers, however, could also be trying to wait out the Trump administration.
Jason Brodsky, policy director at United Against Nuclear Iran, said Tehran “is trying to have it both ways at this point”.
"Mr Zarif is making public overtures to President Trump while also playing the long game in not doing anything to fundamentally jeopardise the nuclear deal, in the event a Democrat were to win the US presidential elections in November 2020," Mr Brodsky told The National.
Waiting out the Trump administration might not necessarily bring the fundamental policy shift that Iran desires, even if the Democrats win the presidency, he said.
“It is untenable for a Democrat in a general election to be advocating rejoining the Joint Comprehensive Plan of Action without any conditions,” Mr Brodsky said.
He said that the agreement would be stale by October 18, 2020 with the arms embargo on Iran expiring under the Security Council resolution endorsing the deal.
Mr Brodsky said that offering unilateral concessions to Iran on the campaign trail “will be deeply unpopular in states like Florida”.
Iran will be holding its elections in the summer of 2021, and it is unclear if Mr Rouhani or Mr Zarif will still be in office.
Brian Hook, the US special representative on Iran, is ignoring Mr Zarif’s statements.
“The real foreign minister of Iran is [Islamic Revolutionary Guard Corps commander] Qassem Suleimani," Mr Hook said on Wednesday.
"We do not fall into the trap of paying attention to what Mr Zarif says."