Iran appointed career diplomat Reza Najafi as its new ambassador to the International Atomic Energy Agency (IAEA) on Tuesday, the official IRNA news agency reported.

Najafi, a disarmament expert, previously headed the political and international affairs bureau at the foreign ministry after chairing the disarmament and international department there.

Iran's Defense Minister Hossein Dehqan warned Tuesday that any Western military action against its ally Syria would threaten the stability and security of the region.

"In case of military action against Syria, the region's security and stability will be threatened," Dehqan said, quoted by the official IRNA news agency.

Any retaliation by Syria and its allies to limited Western military strikes would be restrained, but large-scale intervention aimed at ousting President Bashar Assad would inflame the region, analysts say.

Tensions have ratcheted up dramatically in recent days as Washington has warned Syria's regime it will face action over alleged chemical weapons strikes in Damascus in which hundreds are said to have been killed.

Iran said on Tuesday that it had rejected fresh requests by Ahmed Shaheed, the U.N.'s monitor for human rights in the Islamic republic, to assess the situation on the ground.

"We unfortunately do not consider Ahmed Shaheed to be an impartial rapporteur," foreign ministry spokesman Abbas Araqchi said during his weekly briefing with reporters in Tehran, Iranian media reported.

The Gulf sultanate of Oman is in talks to buy Iranian gas in a 25-year deal worth around $60 billion, Iranian Oil Minister Bijan Namdar Zanganeh said Tuesday.

Zanganeh said Iran and Oman had "signed a memorandum of understanding for the construction of a gas pipeline" under the Sea of Oman, on the east of the strategic Strait of Hormuz, the official IRNA news agency reported.

Knesset Foreign Affairs and Defense Committee chairman Avigdor Lieberman said Tuesday that neither Hizbullah nor the Syrian regime were interested in engaging in war with the Jewish state.

"Hizbullah and (Syrian President Bashar) Assad are not interested in a conflict with Israel. They understand the consequences of Israel entering the battlefield and beginning to play an active role," Lieberman told Israeli Army radio.

Iran has warned a visiting top U.N official of "serious consequences" for the region in case of international military action in Syria, foreign ministry spokesman Abbas Araqchi said Tuesday.

The message was conveyed by Foreign Minister Mohammad Javad Zarif in a meeting on Monday with U.N. political affairs chief Jeffrey Feltman, who is in Tehran for talks that included Syria, Araqchi told reporters.

A senior Israeli delegation visited the White House Monday for high-level talks on the building Syria crisis and the nuclear showdown with Iran.

Officials said U.S. National Security Adviser Susan Rice met retired Israeli major general Yaakov Amidror, Prime Minister Benjamin Netanyahu's top national security adviser.

Kurdish rebels based in north Iraq claimed on Monday to have killed seven Iranian soldiers in clashes last week near the Islamic republic's border with Iraqi Kurdistan.

The Party of Free Life of Kurdistan (PJAK) said two of its fighters had died in the August 22 clashes near the Sardasht border area, populated by Iran's Kurdish minority, apparently the first such deadly violence between the two sides since April 2012.

Syria will allow U.N. inspectors to visit a site near Damascus where an alleged chemical weapons attack is said to have killed hundreds of people, Iran's foreign minister said Saturday.

Mohammad Javad Zarif was quoted by IRNA news agency as saying he had spoken by telephone with his Syrian counterpart, Walid Muallem.