Trump says he 'hopes' Washington not heading to war with Tehran

US President Donald Trump said on Thursday he hoped his country was not going to war with Iran, as tensions between the two nations skyrocket.

The comment came during a meeting with Swiss President Ueli Maurer, whose nation has served as a diplomatic go-between for Iran and the US.

When asked by reporters if Washington was heading towards war with Tehran, Trump responded: "hope not".

Fears of a potential US-Iran conflict have come to the fore in recent weeks, with the US deploying an aircraft carrier strike group and B-52 bomber to the Gulf over alleged threats from Iran.

Washington on Wednesday ordered non-essential diplomatic staff out of neighbouring Iraq following attacks on four oil tankers in the Gulf last weekend.

Maurer and Trump discussed "a range of international issues, including the crises in the Middle East and in Venezuela", said a White House statement according to Reuters.

"President Trump expressed his gratitude for Switzerland's role in facilitating international mediation and diplomatic relations on behalf of the United States," added the statement.

The Washington Post, citing unnamed US officials, reported a day earlier that Trump preferred to take a diplomatic route with Iran rather than risk armed conflict, but worried that some of his advisors were pushing the country towards war.

Iran's Foreign Minister Mohammad Javad Zarif on Thursday rejected the possibility of negotiations between the two nations.

White House spokesman Sarah Sanders, talking to Fox News, denied claims of friction between the president and his advisors.

"He's the one the American people elected. He's going to take in the information and the guidance from all of his national security team and he then will make a decision on what he thinks is the best and safest thing for the American people," she said.

Trump's lack of "appetite" for military conflict with Iran was welcomed by Nancy Pelosi, House Speaker and leading Democratic politician, on Thursday.

Prominent Iranian-Americans, including scholar and TV host Reza Aslan and comedian Maz Jobrani, have called on the US government to avoid war with Iran.

In a letter published by the National Iranian American Council, signatories targeted Secretary of State Mike Pompeo and National Security Advisor John Bolton for pushing "unnecessary conflict" with Iran.

"Bolton has long sought to goad the US and Iran into a war and has no qualms about distorting intelligence to advance his hawkish agenda," read the letter.

"Under Bolton's watch, the Trump administration is repeating the George W. Bush playbook for war with Iraq… These warning signs for a war with Iran cannot be overstated."