Tehran: Iran says it is willing to discuss any issue with the UN nuclear watchdog but maintains it has already answered all outstanding questions about its controversial nuclear program.

Iran's Foreign Ministry spokesman Mohammad Ali Hosseini says the international community is wrong to dispute the answers Tehran has provided to the Vienna-based International Atomic Energy Agency. He spoke on Sunday at his weekly media briefing.

The IAEA said on Wednesday that it had reached a "milestone" agreement with Iran that aims to provide answers about allegations Tehran tried to develop nuclear weapons under cover of a peaceful atomic program.

Iran's official news agency has said the deputy chief of the IAEA, Olli Heinonen, will revisit Iran on Monday to discuss its nuclear programme.

The head of the UN's nuclear watchdog on Sunday confirmed the report that a senior agency official will visit Iran again.

Mohamed ElBaradei, chief of the IAEA, said IAEA Deputy Director General Olli Heinonen will travel to Iran, but did not give more details.