TEHRAN - The head of the UN's nuclear watchdog, Yukiya Amano, arrived in Tehran Monday to hold talks with Iran after the country and six world powers failed to reach an agreement in Geneva last weekend.

Amano will lead the planned talks between Iran and the Vienna-based International Atomic Energy Agency (IAEA) in Tehran, said Ali-Akbar Salehi, head of the Atomic Energy Organization of Iran.

Before leaving Vienna airport for Tehran on Sunday, Amano said he hoped the coming meeting would "produce concrete results" to resolve the outstanding issues.

The IAEA has held 12 rounds of meetings with Iran since 2011, as it wants Tehran to answer allegations that it was trying before 2003, and possibly since, to develop nuclear weapons.

Iran denies seeking or ever having sought nuclear weapons and has refused IAEA requests to visit sites where activities are alleged to have taken place, consult documents and speak to certain scientists.

Amano also expressed hope that the agency and Iran would build on the new proposal of practical measures Iran presented in the last round of talks between the two sides in Vienna last month.

Meanwhile, the talks between Iran and the five permanent members of the UN Security Council - Britain, China, France, Russia and the United States - plus Germany, have been more focused on Tehran's current activities, in particular uranium enrichment, with Iran seeking relief on sanctions.

The three-day talks between these parties ended last weekend with no agreement, but a decision to resume in ten days.

Western countries have long been accusing Iran of developing nuclear weapons under the cover of a civilian nuclear program, but Iran says the suspicion is baseless and fabricated, insisting its nuclear program is for peaceful purposes.