US President Donald Trump has said he does not want a war with Iran amid rising tensions between the two countries, according to senior officials.
In a meeting on Wednesday the president told aides he did not want US pressure to turn into a conflict.
The US has deployed warships and planes to the Gulf and withdrawn diplomatic staff from Iraq in recent days.
Officials cited threats from Iran for the moves.
The latest frictions come after Iran suspended its commitments under the 2015 international nuclear deal, and threatened to resume production of enriched uranium.
The accord aimed to cut sanctions on Iran in exchange for an end to its nuclear programme, but the US unilaterally withdrew from the agreement last year and imposed new sanctions.
Tehran has allegedly placed missiles on boats in the Gulf, and US investigators reportedly believe the country damaged four tankers off the coast of the United Arab Emirates - claims Iran has denied.
But when asked by reporters on Thursday if the US was going to war with Iran, Mr Trump answered: "I hope not."
The president's National Security Adviser John Bolton warned Iran there would be "hell to pay" if they harmed the US or its allies last September.
What's the latest?
Iran's Foreign Minister Mohammad Javad Zarif on Friday called on China and Russia to protect the 2015 nuclear deal with "concrete action".
"So far the international community has mostly released statements rather than taking action," Mr Zarif said at a meeting in Beijing with China's Foreign Minister, Wang Yi.
A Twitter account linked to Iranian MP Heshmatollah Falahatpisheh meanwhile reportedly called for a "red desk" in a third country to attempt to manage current tensions between Iran and the US.
The UN Security Council is meeting to discuss the tensions on Friday.
A state department release says Mr Pompeo spoke with Oman's Sultan Qaboos Bin Said Al Said on Wednesday about "Iranian threats to the Gulf region".
The ruler has long served as an intermediary between Iran and the West, including during nuclear deal talks under President Barack Obama.
The call followed Mr Pompeo's trip to Russia, where he said his country "fundamentally" did not seek a conflict, but added that the US would "certainly respond in an appropriate fashion" if US interests were attacked.
Supreme Leader Ayatollah Ali Khamenei earlier this week stressed there would be no conflict.
"We don't seek a war, nor do they," he said in remarks carried on state media.
Reports say two US destroyers passed through the Strait of Hormuz without incident on Thursday.
There are two competing narratives.
The first, which is favoured by US President Donald Trump's administration, is that Iran is up to no good. Preparations are said to have been seen for a potential attack on US targets, though few details have been revealed publicly.
The US has moved reinforcements to the region; it is reducing its non-essential diplomatic personnel in Iraq; and it is reportedly dusting off war plans.
The second narrative lays the blame for this crisis squarely at Washington's door.
According to this narrative, the "Iran hawks" in the Trump administration - people like National Security Adviser John Bolton, or Secretary of State Mike Pompeo - sense an opportunity. Their goal, this narrative argues, is regime change in Tehran.
The reality is that a conflict between the US and Iran - albeit by accident rather than design - is more likely today than at any time since Mr Trump took office.
And one thing should be clear. There is no "drift" towards war. That suggests an involuntary process that people can do little about.
If there is a conflict then it will be down to conscious decision-making, to the calculations and miscalculations of the Iranians and the Americans themselves.
What's happening in the Gulf?
In just a few days, the US has deployed the USS Abraham Lincoln aircraft carrier to the region and reportedly drawn up plans to send 120,000 troops to the Middle East.
Diplomatic staff have been ordered to leave Iraq, and the US military have raised the threat level in the region because of alleged intelligence about Iran-backed forces - contradicting a British general who had said there was "no increased threat".
Dutch and German soldiers said they had suspended their military training programmes in the country.
On Friday, Saudi Arabia accused Tehran of a drone attack on a pipeline, alleging that Houthi rebels in Yemen conducted the strike on Iran's orders.
A state-aligned Saudi newspaper called for the US to launch attacks on the country.
Iran denies the allegations.