Washington must observe the 2015 nuclear deal and halt "economic terrorism" against Iran if it wants to hold talks, Iranian Foreign Minister Mohammad Javad Zarif said Thursday. Iran and the US have been locked in a bitter standoff since last year when President Donald Trump unilaterally pulled out of the deal that gave Iran relief from sanctions in return for curbs on its atomic program. Trump said Monday he was ready to meet Irans 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 Zarif reiterated that message. "The United States is engaged in economic war against the Iranian people, and it wont 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 in Kuala Lumpur after addressing a forum on security in the Islamic world. "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. Trumps announcement this week came after Zarif traveled 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. Zarif also said Thursday that Iran will fast track legal action against a British oil tanker that Tehran seized last month in the Strait of Hormuz. "We will expedite the legal process for the British tanker that is now in our custody after they basically committed sea crimes by taking our ship," he said, adding that Iran will not be lenient about ships in the Persian Gulf that violate laws. The UK-flagged Stena Impero was diverted to an Iranian port on July 19, two weeks after Britain detained an Iranian tanker off the territory of Gibraltar. Washington has called on its allies to join an operation to guard shipping in the Strait of Hormuz, a vital gateway for the worlds oil industry. So far, Britain, Australia and Bahrain have joined the US-led security mission. Washingtons call followed a series of attacks on international merchant vessels, which the United States has blamed on Iran, and the Iranian seizure of a British oil tanker.