The US Defense Secretary says the US is still hoping to guide Iran on "a diplomatic path" and that the two countries are "inching" towards talks.
Mark Esper made the comments on his first visit to London since taking on the role in August.
Speaking alongside UK Defence Secretary Ben Wallace on Friday, Mr Esper praised the work of a US-led maritime security mission in the Gulf region, stating it was deterring Iran from seizing ships.
He said the maritime coalition, made up of the US, UK, Australia and Bahrain, is pushing Iran to enter negotiations: "That has always been our aim here - to get the Iranians on a diplomatic path so we can talk to them.
"The President has been very clear about the willingness to meet with Iran, without precondition to discuss how we move forward and avoid conflict."
Earlier on Friday morning, Mr Esper made a speech at the Royal United Services Institute where he said he was hopeful of talks developing.
He said: "It seems, in some ways, that Iran is inching toward that place where we could have talks and hopefully it’ll play out that way," he told the think-tank.
"‘Inching’ is subtle movements and I think that’s a good thing.”
Tensions between the US and Iran have soared since US President Donald Trump pulled the country out of the 2015 nuclear deal and reimposed sanctions.
Earlier this year, the US sent an aircraft carrier strike group to the region amid the escalating tensions.
The UK has also deployed more military assets to the region and accused Iran of "failing to respect international maritime rules" after a British-flagged tanker was seized by Iranian forces.
When asked by reporters about the ongoing US-Taliban peace talks, Mr Esper refused to comment.
He also declined to comment on when the US could begin troop withdrawal from Afghanistan.
Mr Wallace said he welcomed the US' efforts in the talks but said any deal must not "put at risk the United States' or Britain's security".