Iran will not be pressured into negotiations by the United States, but if authorities in Washington act towards it with respect, Tehran will respond accordingly, Foreign Minister Mohammad Javad Zarif said on Monday.
The two countries have been drawn into starker confrontation since May, when Washington mounted pressure on Tehran by ordering all countries to halt imports of Iranian oil, and the future of Iran's 2015 nuclear pact with world powers hangs in the balance.
Washington has tightened sanctions and dispatched extra forces to the Middle East, and US fighter jets came within minutes of conducting air strikes on Iran last month after Tehran downed an unmanned American drone.
"Iran will never yield to pressure from the United States... If they want to talk to Iran, they should show respect," Zarif said in a speech broadcast live on state TV.
"Never threaten an Iranian ... Iran has always resisted pressure and has responded with respect when respected."
US President Donald Trump has called for negotiations with Iran with "no preconditions".
But Tehran has ruled out talks with Trump until the United States returns to the nuclear pact, which he quit last year, and has referred to the latest US sanctions - on Supreme Leader Ayatollah Ali Khamenei and other senior officials - as "idiotic".
Khamenei has ruled out any negotiations with the United States while President Hassan Rouhani, who has taken a more pragmatic stance on relations with Washington, had previously signaled talks might be possible if sanctions were lifted.
In reaction to the US withdrawal from the nuclear deal, Iran said in May that it had quadrupled its production of low enriched uranium, and diplomats say it is days away from exceeding the maximum amount of the substance allowed under the deal.
In last-ditch talks in Vienna on Friday to persuade Iran to back off from its plans to breach the limits, Iran's envoy said European countries still party to the nuclear deal had offered too little in return.