IAEA Director General Yukiya Amano-June 4, 2014
International Atomic Energy Agency Director General Yukiya Amano waves as he arrives for a board of governors meeting at IAEA headquarters in Vienna June 4. Reuters/Heinz-Peter Bader/Files

Update 11:55 a.m.: VIENNA/DUBAI (Reuters) - Iran has given a firm commitment to cooperate with a U.N. nuclear watchdog investigation into suspected atomic bomb research, the head of the agency said after what he described as a "useful" visit to Tehran on Sunday. Yukiya Amano made the trip ahead of an Aug. 25 deadline for Iran to provide information relevant to the International Atomic Energy Agency's long-running inquiry into what it calls the possible military dimensions of the country's nuclear programme.

Original post:

(Reuters) -- U.N. nuclear-agency chief Yukiya Amano began talks in Tehran Sunday with President Hassan Rouhani and other senior officials to push for progress in a long-running investigation into Iran’s suspected atomic-bomb research. Amano’s trip comes ahead of an Aug. 25 deadline for Iran to provide information relevant to the International Atomic Energy Agency’s, or IAEA’s, inquiry into what it calls the possible military dimensions of the country’s disputed nuclear program.

The issue is closely tied to high-profile nuclear negotiations with six world powers aimed at resolving the decade-old standoff over Tehran’s atomic activities, suspected by the West of having military objectives.

Amano arrived late Saturday on his second visit to Iran since the election of Rouhani. Although Tehran rejects the West’s suspicions about its nuclear program, it has promised to work with the IAEA to clear them up since the pragmatist Rouhani became president in mid-2013.

No details have emerged from the IAEA chief’s meetings with Rouhani or Foreign Minister Mohammad Javad Zarif, who leads Iran’s negotiating team with the world powers -- the U.S., China, France, Germany, Russia and the U.K.

“Mr. Amano’s previous visit was too short to allow for a meeting with President Rouhani, so it has been arranged now in order to convey the Islamic Republic’s expectations to the IAEA at the highest levels,” Iran’s ambassador to the IAEA, Reza Najafi, was quoted as saying by official IRNA news agency.

Deal Uncertain

With major gaps remaining over the permissible future scope of Iran’s uranium-enrichment program, the talks between Iran and the world powers in mid-July were extended until Nov. 24, and a final deal is far from certain.

Rouhani’s eagerness to end the nuclear standoff as part of an effort to salvage the country’s sanctions-hit economy has been hampered by Islamic hardliners’ opposition to any major concession to the West on the nuclear file.

Iran has agreed to clarify two other issues by Aug. 25 concerning alleged work on explosives and computer studies related to calculating nuclear explosive yields. They were among 12 specific areas listed in an IAEA report issued in 2011 with a trove of intelligence indicating a concerted weapons program that was halted in 2003 -- when Iran came under increased international pressure.

The intelligence also suggested some activities may later have resumed.

(Reporting by Mehrdad Balali; Editing by Yara Bayoumy and Sophie Hares)