In his most significant speech on foreign policy in several months, Khamenei also vowed that Iran would not halt sensitive work on its controversial nuclear programme as demanded by the West.
“Cutting ties with the United States is one of our basic policies. We have never said that they will be cut for ever,” Khamenei told students in a speech in the central city of Yazd.
“The conditions of the US government are such now that it is harmful for us to resume relations,” he said, describing the United States as a global “danger”.
“Despite some talkative people’s claims, it has no benefit for the Iranian nation.
“The day that relations with the United States are beneficial to the Iranian nation, I will be the first one to approve of that,” he said.
The position of Khamenei as Iran’s undisputed number one, which he holds for life, takes him above the fray of day-to-day politics. Such statements on major issues like US relations are made only occasionally and are hugely significant.
Tehran and Washington have had no diplomatic links since 1980 when the United States cut relations amid the siege of the US embassy in Tehran by Islamist students that was to last a total of 444 days.
Exchanges since then have been marked by acrimony and suspicion, although the two sides held talks on Iraqi security last year in the highest level official contacts for almost three decades.
The United States was a major ally of the imperial regime of the last shah of Iran Mohammad Reza Pahlavi — who was deposed by the Islamic revolution in 1979 — supplying vast quantities of military equipment.
Khamenei said the current US hostility to Iran had not been provoked by firebrand statements by President Mahmoud Ahmadinejad and other officials against Tehran’s arch enemy, known here as the “Great Satan”.
“Its enmity is with the principles of the Iranian nation and it has been there since the beginning of the Islamic revolution,” he said.
“Resuming relations will create the possibility of US influence (in Iran) and the coming and going of US spies,” he said. The massive compound in central Tehran that housed the US embassy is known locally as the “Den of Spies”.
The two sides remain at loggerheads over the Iranian nuclear programme, with the United States leading Western calls for Iran to suspend uranium enrichment, which Washington fears could be used to make nuclear weapons.
“The nation, which is carrying out enrichment by relying on itself, will build the (nuclear) plants too. If the nation had not done enrichment, it would be behind by years,” he said.
Russia is building and supplying the fuel for Iran’s first 1,000 megawatt nuclear power plant in the southern city of Bushehr but Khamenei reaffirmed his desire for Iran to construct and supply atomic power plants independently.
“In the next 20 years, we should have at least 20,000 megawatts of nuclear electricity,” added Khamenei.
He angrily lashed out at moderates inside Iran who had cautiously suggested that the country should consider suspending enrichment to de-escalate the nuclear crisis.
“Some people challenge the system and the government over this and, in line with the enemy, seek to create disappointment. The nation should be watchful of such infiltrations.”
Western powers have offered Iran full negotiations including with the United States on the nuclear standoff if it suspends enrichment. But Tehran has always responded it would only consider talks without preconditions.
Iran has always insisted its nuclear programme, revived after Khamenei became supreme leader in 1989, is aimed solely at producing nuclear energy for a growing population whose fossil fuels will eventually run out.
The United States has never ruled out military action against Iran but a US intelligence report that said Tehran halted a nuclear weapons programme in 2003 has taken the heat out of the crisis for the moment.
