Tehran and Washington have been locked in a bitter standoff since last year when US President Donald Trump unilaterally pulled out of the 2015 deal that gave Iran relief from sanctions in return for curbs on its atomic programme.

Trump said Monday he was ready to meet Iran's President Hassan Rouhani within weeks, in a potential breakthrough reached during a G7 summit in the French seaside resort of Biarritz.

But Rouhani has said Washington must first lift sanctions imposed since its withdrawal from the nuclear deal, and Foreign Minister Mohammad Javad Zarif reiterated that message.

"The United States is engaged in economic war against the Iranian people, and it won't be possible for us to engage with the United States unless they stop imposing a war, engaging in economic terrorism against the Iranian people," he told reporters during a visit to Malaysia,

"We spoke to the United States, we spoke at length with the United States, we reached an agreement and they need to implement the agreement that we have reached before they expect to have more talks," he added, referring to the nuclear deal.

Iran was still talking to other world powers involved in the deal, he said.

"If (the US) wants to come back to the room there is a ticket that they need to purchase, and that ticket is to observe the agreement," he added.

Trump's announcement this week came after Zarif travelled to France on Sunday for the second time in a matter of days, and held meetings on the sidelines of the G7 summit.

US Defense Secretary Mark Esper also called Wednesday for Iran to enter discussions with the US to ease tensions in the Gulf region.

"We are not seeking conflict with Iran. We want to engage with them diplomatically," Esper said.

In response to the US withdrawal and its imposition of crippling sanctions, Iran has hit back by abandoning commitments under the nuclear deal.