The six Gulf states have sharpened their tone against their neighbour Iran, demanding an immediate halt to its "interference" in their internal affairs while urging action to halt mass killings and violations of international law in Syria.
Concluding a two-day summit in Manama, the Gulf Cooperation Council members voiced support for Bahrain while lashing out at Tehran, which they accuse of fuelling a Shia-led uprising in the host country last year.
"The council expressed its rejection and condemnation of the continuing Iranian interference in the affairs of the Gulf Cooperation Council's states and called on Iran to stop these policies," a joint statement issued at the end of the summit said on Tuesday.
The council said they "reject and denounce" Iran's "continued interference" in their internal affairs that increase regional tension and threaten security and stability.
The six states - Saudi Arabia, Qatar, Bahrain, Kuwait, Oman, and the United Arab Emirates - also condemned Iran's "continued occupation of the three Emirati islands" of Abu Musa, Greater Tunb and Lesser Tunb, which lie in the strategic Strait of Hormuz entrance to the Gulf.
In addition to the dispute over the islands, relations between Iran and most GCC states have been further strained since Gulf troops rolled into Bahrain last year to help put down the protests.
Sheikh Khalid Bin Ahmed Al-Khalifa, Bahrain's foreign minister, said: "There is very serious threat from many ways [by Iran]. There is political threat, as you said, lots of meddling in the affairs of the GCC states ... There is an environmental threat coming to our region from the technology used in some of the nuclear facilities, and there is of course the threat looming always regarding the nuclear programme of a conflict that can erupt any moment, so the threat level is quite high."
On the conflict in Syria, the statement, read out by GCC Secretary-General Abdulatif al-Zayani, added: "We ask the international community for serious and swift moves to stop these massacres and these severe attacks."
The GCC leaders expressed "deep sadness over the continued shedding of blood by the regime and the destruction of cities and infrastructure, making political transition a demand which must be rapidly implemented".
The GCC states also affirmed their support for the newly-formed opposition National Coalition "as the legitimate representative of the Syrian people".
The summit had opened on Monday with a call for closer economic integration and unity in the face of the turmoil which has swept much of the Middle East and North Africa.