Foreign ministers from the Gulf Co-operation Council (GCC) will meet on Saturday before a summit that some analysts expect will call for intensified diplomacy with Iran.
The GCC members are Saudi Arabia, UAE, Kuwait, Qatar, Bahrain and Oman.
N Jahardhan, analyst at the Gulf Research Centre, said: "GCC countries are getting worried that things in Iran are getting out of hand.
"The GCC realises Iran is definitely a threat ... Things have reached a critical stage and they feel they will bear the brunt of any escalation. It is clear that there is no defined policy in Iran about what to do if it is attacked."An official associated with the two-day meeting, to be held in Abu Dhabi, capital of the UAE, said: "There is concern that Iran's nuclear programme could be weaponised. At the end of the day they [Iranians] are building a nuclear reactor across the Gulf.
"There is also concern that if there is any military action (against Iran), Iran might retaliate and attack pro-US allies in the Gulf."
Iran's nuclear programme is fuelling regional and Western fears that it is seeking to develop weapons, which Tehran denies.
Any talks by the GCC with Iran would also focus on Tehran's alleged influence in Iraq. Saudi Arabia and the US have already accused Iran of meddling in Iraqi affairs.
"There is also concern that if there is any military action (against Iran), Iran might retaliate and attack pro-US allies in the Gulf"
A Saudi official said Riyadh was keen the Gulf leaders should demand that Syria co-operate with a UN inquiry into the killing of Rafiq al-Hariri, the former Lebanese prime minister who was assassinated in February.Syria denies any part in the killing.
"King Abdullah has taken the lead to persuade Syria to meet UN demands and Riyadh expects the summit to reflect Saudi desire for full Syrian co-operation," the official said.
Another official said the GCC was likely to issue a strongly worded statement on Syria. "They want Syria to comply with the United Nations and stop dragging its feet," he said.
The Security Council is reviewing a report by Detlev Mehlis, its investigator, who said new evidence implicated Syria in al-Hariri's murder.
Free Trade Agreements
Saudi Arabia had helped to negotiate a deal between Syria and the United Nations by persuading Damascus to agree to the questioning of five Syrians about al-Hariri's assassination.
On the economic front, analysts expect talks to focus on turning bilateral free trade agreements (FTAs) between member states and other countries into deals with the whole bloc.
The GCC has reluctantly agreed to individual bilateral FTAs with Washington, even though they infringe on a joint tariff deal, but said trade pacts might not be signed with other states.
Ghazi al-Gosaibi, the Saudi employment minister, has also said ministers will propose a six-year limit for expatriates to stay in Gulf states, which rely on millions of foreign workers.
He said that this was to pre-empt any international laws that might force states to grant citizenship to long-term residents.