The UN's atomic watchdog is appealing for more money to fund increased inspections in Iran.
The International Atomic Energy Agency (IAEA) is tasked with verifying that Tehran is adhering to the terms of a six-month accord on its nuclear program.
The interim deal offers some sanctions relief in exchange for curbing uranium-enrichment work.
Speaking at a meeting of the IAEA's governors in Vienna on January 24, Director-General Yukiya Amano said the agency would need additional funding of some 5.5 million euros ($7.5 million).
Describing the agreement as an "important step forward" toward achieving a comprehensive solution to the nuclear dispute with Iran, Amano nevertheless said there was "still a long way to go."
The nuclear deal, which came into force on January 20, was reached with the UN Security Council's permanent members, plus Germany, in November.
Based on reporting by AFP and Reuters