A summit of Gulf Arab leaders in Bahrain demanded Iran end what they called interference in the region, reiterating their long-held mistrust of their regional rival.

A communique issued at the end of a two-day summit of the six-member Gulf Cooperation Council (GCC) also called on the international community to bring a swift end to massacres and violations of international law in Syria.

"The council expressed its rejection and condemnation of the continuing Iranian interference in the affairs of the GCC states and called on Iran to stop these policies," the statement said.

On 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 that contradict all religions and international laws and humanitarian principles."

The statement called on the international community "to provide all forms of urgent humanitarian aid" for the people of Syria.

Kuwait said on Monday it would host an international humanitarian donor conference for Syria at the end of January, amid growing concern for millions of Syrians suffering war, homelessness and winter cold.

Gulf Arab leaders have long called for Syrian President Bashar al-Assad to step down, and in November the GCC recognised a newly-formed opposition coalition as the legitimate representative of the Syrian people.

The communique did not elaborate on Iran, but the most common Gulf Arab complaint about alleged Iranian meddling in the region relates to Bahrain, which has repeatedly accused Tehran of interference in its internal politics.

Iran sees the Gulf as its own backyard and believes it has a legitimate interest in expanding its influence there.

Bahraini Foreign Minister Khalid Bin Ahmed Bin Mohammed Al Khalifa told reporters Iran posed a "very serious threat".

"Politically, (there is) lots of meddling in the affairs of GCC states; an environmental threat to our region from the technology used inside nuclear facilities; and there is of course the looming nuclear programme," he said, referring to Iran's disputed atomic work.

"So the threat level is quite high, but we are ready if faced with circumstances that require action." – Reuters