* U.N. nuclear chief says committed to "dialogue" with Iran
* IAEA seeks deal with Iran on stalled investigation
* Israel and Iran accuse each other of threatening peace
VIENNA, Jan 25 (Reuters) - The U.N. nuclear watchdog chief has underlined to Israel's president the need to resolve differences with Iran diplomatically, Yukiya Amano's office said on Friday, rather than war as Israeli leaders have mooted.
Israel, widely believed to be the only nuclear-armed state in the Middle East, has threatened possible military action if diplomacy and sanctions fail to prevent arch-adversary Iran from developing nuclear weapons. Iran says its uranium enrichment programme is for peaceful energy purposes only.
Amano said in a meeting with Israeli President Shimon Peres at the World Economic Forum in Switzerland on Thursday that the International Atomic Energy Agency had intensified "dialogue" with Tehran, the IAEA said in a statement.
That was a reference to the IAEA's year-long push - so far fruitless - to negotiate a framework deal with Iran allowing the Vienna-based U.N. agency to resume a long-stalled investigation into suspected nuclear weapons research by Tehran.
Director-General Amano "made clear the Agency's commitment to dialogue, and the need to resolve issues with Iran by diplomatic means", the IAEA said in a statement.
Analysts say any brewing or actual military action against Iran will dim the chance of Iran opening up to IAEA investigators and spur Tehran to expel IAEA inspectors tasked with ensuring civilian safeguards on Iran's nuclear activity.
Israeli Prime Minister Benjamin Netanyahu, in an election victory speech on Wednesday, said preventing Iran from obtaining nuclear arms would be the next government's main challenge.
Iran, which denies Israel and Western accusations that it is seeking to develop the capability to make nuclear bombs, says it is Israel's assumed nuclear arsenal that poses a threat to peace and stability in the volatile Middle East.
Amano also "stressed the importance of a successful conference" on a Middle East free of nuclear and other weapons of mass destruction, the IAEA statement said.
Talks on banning nuclear weapons in the region had been due last year. But the United States - a co-sponsor of the planned conference - said in November the meeting would not occur and did not make clear when it would take place.
U.S. and Israeli officials have said a nuclear arms-free zone in the Middle East could not be a reality until there was broad Arab-Israeli peace and Iran curbed its nuclear programme.
Iran and Arab states have criticised the decision to put off the talks, with Tehran blaming Washington for what it called a "serious setback" to the nuclear Non-Proliferation Treaty (NPT). (Reporting by Fredrik Dahl; Editing by Mark Heinrich)