Iran's supreme leader said the current situation with the United States was "unsolvable," and that Tehran would never bow to pressure to obey Washington, amid a standoff with Western powers over its nuclear program, state media reported on Sunday.

The Islamic Republic suspended nuclear negotiations with the United States after the U.S. and Israel bombed its nuclear sites during a 12-day war in June.

Ayatollah Ali Khamenei's comments come after Iran and European powers agreed on Friday to resume talks to try to restart full negotiations on curbing Tehran's nuclear enrichment work.

"They want Iran to be obedient to America. The Iranian nation will stand with all of its power against those who have such erroneous expectations," Ayatollah Ali Khamenei was reported as saying.

"People who ask us not to issue slogans against the U.S. ... to have direct negotiations with the U.S. only see appearances ... This issue is unsolvable," he added.

France, Britain and Germany have said they could reactivate United Nations sanctions on Iran under a "snapback" mechanism if Tehran does not return to the table.

The European states, along with the U.S., say Iran is working towards developing nuclear weapons. Iran says it is only interested in developing nuclear power.