The U.N. nuclear watchdog’s board has condemned Iran for failing to cooperate fully with the agency, the second time it has done so in just five months.

Iran announced Friday it was activating new advanced centrifuges – which enrich uranium for the country’s nuclear program – after the United Nations’ nuclear watchdog criticized the country for not cooperating with the agency.

The action could lead to sanctions against Tehran, which has barred international monitoring of its accelerated uranium enrichment efforts.