Fereydoun Abbasi-Davani, the head of Iran’s Atomic Energy Organization, did not spell out whether he meant unrestricted access for the United Nations’ International Atomic Energy Agency (IAEA) in its probe into Tehran’s nuclear program.

Since talks between global powers and Iran foundered in January, Russia has advocated a phased plan in which Tehran would address concerns that it may be seeking nuclear weapons, and be rewarded with an easing of sanctions.

But Abbasi-Davani made clear Iran has no intention of suspending its uranium enrichment program, a condition enshrined in a series of United Nations Security Council sanctions resolutions imposed on Tehran since 2006.

Western nations suspect Iran is trying to use its nuclear program to develop atomic weapons. The Islamic Republic has denied the charge, saying it wants to produce nuclear energy.

The IAEA, which in a report last week said it was “increasingly concerned” about possible nuclear weapons development work in Iran, has long complained of a lack of Iranian cooperation with agency inspectors.

It has called on Tehran to implement the IAEA’s so-called Additional Protocol, which would give the UN agency unfettered access to Iranian sites at short notice.

While granting inspectors regular access to its declared nuclear facilities, including the Natanz enrichment site, the Islamic state has so far refused to allow it wider inspection powers under the IAEA’s Additional Protocol.

Iran has recently sought to demonstrate increased openness about its nuclear program, allowing a senior IAEA official rare access to a research and development facility last month.

But Western diplomats have dismissed this as a “charm offensive” and an attempt by Iran to ease international pressure on the country, while forging ahead with an enrichment drive that can have both civilian and military purposes.

“By lifting the UN sanctions ... the International Atomic Energy Agency can have full supervision over Iran’s nuclear work for five years,” Abbasi-Davani told ISNA.

He said the IAEA’s allegation of possible military-linked nuclear work was “fabricated and baseless.”

In a comment making clear Tehran has no intention of halting such work, he said Iran planned to increase the number of uranium enrichment machines in its nuclear facilities over the next six months.

“We also plan to set up new production lines to produce a new generation of centrifuges,” Abbasi-Davani said.

For years, Tehran has been seeking to replace the breakdown-prone 1970s vintage model of centrifuge it now uses to refine uranium, but the changeover has been hampered by sanctions restricting access to vital components, analysts say.

Abbasi said Iran was not yet ready to mass-produce the new centrifuges.