Iran's announcement came after the four Western powers brought a censure motion targeting the Islamic republic at the 35-nation board of the International Atomic Energy Agency (IAEA). The resolution was adopted on Thursday.

"We note with serious concern Iran's announcement... that, instead of responding to the resolution with cooperation, it plans to respond with further expansion of its nuclear program in ways that have no credible peaceful rationale," the four nations said in a joint statement released by the US State Department.

"We expect Iran to reengage on the path of dialogue and cooperation with the agency."

On Friday, Iran said it would launch a "significant series of new and advanced centrifuges of various types."

Centrifuges are the machines that enrich uranium transformed into gas by rotating it at very high speed, increasing the proportion of fissile isotope material (U-235).

"At the same time, technical and safeguards cooperation with the IAEA will continue, as in the past" and within the framework of agreements made by Tehran, said a joint statement from Iran's foreign ministry and its atomic energy organization.

Behrouz Kamalvandi, a spokesman for Iran's atomic energy organization, on Friday said the new measures are mostly related to uranium enrichment.

Tensions are running high over Iran's atomic program, with critics fearing that Tehran is attempting to develop a nuclear weapon -- a claim the Islamic Republic has repeatedly denied.

In their four-way statement Saturday, the United States, Britain, France and Germany welcomed the adoption of the IAEA resolution, saying it was in response to Iran's "continued failure" to cooperate with the watchdog in a timely manner.

The resolution, seen by AFP, says it is "essential and urgent" for Iran to "act to fulfill its legal obligations" under the Non-Proliferation Treaty (NPT) ratified in 1970.

The text also calls on Tehran to provide "technically credible explanations" for the presence of uranium particles found at two undeclared locations in Iran.

In addition, Western powers are asking for a "comprehensive report" to be issued by the IAEA on Iran's nuclear efforts "at the latest" by spring 2025.

"We hope Iran will take the opportunity between now and that report to finally provide the information and cooperation needed to resolve these issues, so that the agency is able to provide assurance that Iran's program remains exclusively peaceful," the Western powers said Saturday.