Iran will not lift its ban on talks with the US, Supreme Leader Ayatollah Ali Khamenei said on Sunday, describing the two countries as implacable foes on the eve of the 40th anniversary of the seizure of the US embassy in Tehran.

“One way to block America’s political infiltration is to ban any talks with America. It means Iran will not yield to America’s pressure,” Khamenei, who is Iran’s top authority, was quoted by state TV as saying.

“Those who believe that negotiations with the enemy will solve our problems are 100% wrong,” he said.

Relations between the two foes have reached a crisis over the past year after US President Donald Trump abandoned a 2015 pact between Iran and world powers under which Tehran accepted curbs to its nuclear programme in return for lifting sanctions.

Washington has reimposed sanctions aimed at halting all Iranian oil exports, saying it seeks to force Iran to negotiate to reach a wider deal. Khamenei has banned Iranian officials from holding such talks unless the US returns to the nuclear deal and lifts all sanctions.

The anniversary of the seizure of the US embassy shortly after Iran’s 1979 Islamic Revolution is marked in Iran with annual demonstrations of crowds chanting “Death to America” across the country.

The embassy capture cemented the hostility between the two countries which has remained a central fact in Middle East geopolitics.