Nuclear talks between Iran and six world powers, including the United States, are slated to begin Friday in Istanbul, Iranian state media said Sunday.

Iran’s official English-language Press TV quoted an unnamed official at the Supreme National Security Council, which handles the country’s nuclear program, as setting the date and place of the talks. Reuters quoted a spokeswoman for the European Union foreign policy chief confirming that the talks would take place this week in Istanbul.

The site had been in question after Iranian politicians declared that Turkey, a key negotiator in the talks, was no longer neutral ground because it actively opposes Syria, an Iranian ally. The uncertainty about the location had prompted Western worries that Iran was not planning to seriously engage the world powers — the United States, Russia, China, Britain, France and Germany — in the first talks since January 2011.

The six nations are expected to press Iran to accept curbs on its nuclear program that would make it far more difficult for Tehran to build a nuclear weapon. A key demand, Western diplomats say, is that Iran halt production at its uranium-enrichment plant near Qom, a ­Shiite holy city about 90 miles south of Tehran, which was built in mountain tunnels beyond the reach of all but the most advanced bombs and missiles. The United States also expects Iran to fully suspend production of 20 percent enriched uranium, which Iran says it needs to power a 43-year-old U.S.-built nuclear test reactor that produces radio isotopes.

In a signal that Iran is willing to negotiate over its stockpile of 20 percent enriched uranium, the head of the Atomic Energy Organization of Iran, Fereydoon Abbasi, said Sunday that his country was considering a stop to the activity and lowing the enrichment levels.

“We do not produce more 20 percent fuel than we need,” Abbasi told the Iranian Students’ News Agency. He said it was easy to change the centrifuges now enriching uranium up to 20 percent and use them for making nuclear fuel up to 3.5 percent enriched. “Our systems are capable of making this change,” Abbasi said.

The Western request to close the facility near Qom, called Fordow, is “not logical,” Abbasi said, stressing that the mountain bunker was no different from Iran’s main nuclear facility at Natanz. He also said that Iran’s only semi-operating nuclear reactor, in the town of Bushehr, was running on fuel provided by Russia.

Last month, some prominent Iranian elected officials and analysts — many of them close to the country’s hard-line leadership — said it was highly unlikely that Iran would accept even a temporary halt in its production of enriched uranium. They said recent economic sanctions and military threats against the country have made Iranian leaders even more determined to continue enriching uranium, despite the worsening toll on Iran’s currency and oil industry.

“Please do not make the general public expect any freeze on the enrichment of uranium,” said Hossein Sheikholeslami, a former Iranian ambassador to Syria who was once a leader of the student movement that took 52 U.S. Embassy workers hostage in 1979. “We regard this as our inalienable right.”

The enrichment facility near Qom houses Iran’s fallback nuclear energy program: a series of centrifuges hidden deep inside a mountain bunker. Iran has said that it built the facility to protect its nuclear technology from attack by Israel or the United States.

“Closing down that site is out of the question,” said Sheikholeslami, who is a key adviser to Iran’s former top nuclear negotiator, Ali Larijani.

But Iran might be willing to talk about its stockpile of the higher-grade uranium, he said. Iranian officials say they were forced to enrich the uranium to a higher level in order to keep their U.S.-built reactor running after Western powers refused to deliver new batches of fuel in 2009.

“I don’t think we can trust the West for now giving us that fuel, but Iran’s negotiating team might be willing to debate this option,” Sheikholeslami said.