Russian Defense Minister Sergei Shoigu made an unsubstantiated allegation that Ukraine was preparing to launch a so-called dirty bomb. Shoigu leveled the charge over the weekend in calls to his British, French, Turkish and U.S. counterparts. Britain, France and the United States rejected it out of hand as “transparently false.”

Ukraine also dismissed Moscow’s claim as an attempt to distract attention from the Kremlin’s alleged plans to detonate a dirty bomb, which uses explosives to scatter radioactive waste to sow terror.

Energoatom, the Ukrainian state enterprise that operates the country’s four nuclear power plants, said Russian forces have carried out secret construction work over the last week at the occupied Zaporizhzhia Nuclear Power Plant in Ukraine.

Russian officers controlling the area won’t give access to Ukrainian staff running the plant or monitors from the U.N.’s atomic energy watchdog that would allow them to see what the Russians are doing, Energoatom said Tuesday in a statement.

Energoatom said it “assumes” the Russians “are preparing a terrorist act using nuclear materials and radioactive waste stored at” the plant. It said there were 174 containers at the plant’s dry spent fuel storage facility, each of them containing 24 assemblies of spent nuclear fuel.

“Destruction of these containers as a result of explosion will lead to a radiation accident and radiation contamination of several hundred square kilometers (miles) of the adjacent territory,” the company said.

It called on the International Atomic Energy Agency to assess what was going on.

كان من المقرر أن يعقد مجلس الأمن الدولى مشاورات مغلقة حول مزاعم القنبلة القذرة فى وقت لاحق اليوم الثلاثاء بناء على طلب روسيا.

طلبت روسيا من المجلس تشكيل لجنة للتحقيق في مزاعمها بأن الولايات المتحدة وأوكرانيا تنتهكان الاتفاقية التي تحظر استخدام الأسلحة البيولوجية في المعامل في أوكرانيا.