ABU DHABI, Dec. 19 (Xinhuanet) -- Gulf Arab leaders placed top emphasis on maintaining regional security and stability during a two-day summit which wrapped up here on Monday amid rising concerns over Iran's nuclear program and the international probe of the killing of Lebanon's ex-premier Rafik al-Hariri.

   The Gulf Cooperation Council (GCC), a regional alliance grouping Saudi Arabia, Kuwait, Qatar, Oman, Bahrain and the United Arab Emirates, voiced concerns during its annual summit over the Iranian nuclear issue and Syria's cooperation with the United Nations in the investigation into Hariri's death.

   But the Gulf Arab alliance, eager to defuse tensions and maintain regional stability, has cautiously worded its final declaration reached during the summit, avoiding provoking Iran and Syria.

   NUCLEAR-FREE GULF

   GCC leaders unanimously called for a Gulf region free from nuclear weapons and weapons of mass destruction, but refrained from singling out Iran's nuclear case in the final statement.

   The Gulf Arab alliance expressed "regret" over the lack of progress in talks between the group and Iran over regional stability and security, the statement said.

   Meanwhile, GCC Secretary General Abdul Rahman al-Attiya said at a press conference held after the summit that the GCC was "justified" in showing concerns over Iran's nuclear program, stressing that the Iranian nuclear facilities were very close to the GCC countries.

   He also voiced worries that any possible leakage of Iran's nuclear facilities might wreak havoc on GCC countries, urging Iran to establish an early-warning system and inform the bloc as soon as possible in case of such incidents.

   But Yousif bin Alawi, Oman's Minister in charge of Foreign Affairs, said that the GCC did not intend to impose any pressure on Iran and that the group wanted to maintain good relations with its Shiite-dominated neighbor.

   Iran's nuclear issue, in the world limelight and closely watched by Gulf Arab countries, has been a heatedly-discussed topic during the GCC summit, said delegates.

   The alliance has earlier urged Iran to stick to the peaceful nature of its nuclear program and tackle the issue logically with Western countries and Gulf Arab countries to avoid escalating tensions that might spill over to the Gulf area and do harm to the oil-rich region.

   Delegates said the alliance, though concerned, espouses a peaceful settlement of the Iranian nuclear issue.

   Meanwhile, the GCC has declared that it will not mediate between the United States, which accuses Tehran of developing nuclear weapons under a civilian front, and Iran over the nuclear issue, saying Washington has not asked for GCC's mediation.

   Iran categorically denies Washington's charge.

   Meanwhile, GCC leaders urged Israel to join the Nuclear Non-Proliferation Treaty and subject its nuclear facilities to international inspection.

   Officials of GCC countries have termed Israel's nuclear weapons as a threat to regional stability and security.

   Widely believed to be the only nuclear power in the region, Israel has never admitted or denied that it has nuclear weapons.