Iranian Foreign Minister Mohammad Javad Zarif says there is "no possibility" of talks with the United States to reduce spiraling tensions.
Zarif's remarks on May 16 came a day after U.S. President Donald Trump said he was confident that Tehran will "soon" seek to negotiate with Washington.
Trump's remarks follow comments he made on May 9 when he said he did not rule out a military confrontation with Iran.
Tensions have risen since Trump in May 2018 pulled the United States out of a landmark 2015 nuclear deal that Iran signed with six world powers and unilaterally reintroduced sanctions.
The accord provided Tehran with relief from sanctions in return for curbs on its nuclear program.
Trump has ordered a beefing-up of U.S. military assets in the Middle East and Persian Gulf, citing possible threats from Iran, and the State Department also ordered the evacuation of all nonessential personnel from the U.S. Embassy in neighboring Iraq.
On May 16, two major pro-Iran armed groups in Iraq rejected suggestions that U.S. Embassy personnel in the country were at risk.
“No, there is no possibility for negotiations," Zarif told reporters in Tokyo, where he held talks with Japanese officials on May 16. "I don't know why President Trump is confident, but it's totally wrong."
In pulling out of the nuclear deal, Trump said the terms were not tough enough to prevent Iran from developing nuclear weapons and did not address Iran's missile program or Tehran's alleged support for militants in the region.
Iran denies it supports insurgent activity and has said its nuclear program is strictly for civilian energy purposes.
Zarif said on May 16 that Tehran was showing "maximum restraint" despite the U.S. withdrawal from deal and accused Washington of an "unacceptable" escalation of the crisis.
British Foreign Secretary Jeremy Hunt said on May 16 that he shared Washington's "assessment of the heightened threat posed by Iran."
According to Iranian state media, Zarif is set to visit China on May 17 for talks on "regional and international issues" including the 2015 nuclear deal with world powers.