Gulf countries, while siding with Washington against Islamic State jihadists, are struggling to build a common front because of differences within their own ranks and with non-Arab Iran.
US President Barack Obama is sending his Secretary of State John Kerry to the Middle East to try to build strong regional support against IS, which is rampaging through Iraq and Syria.
But "we don't have a strategy yet" to defeat the jihadists, he acknowledged on Thursday.
Saudi Foreign Minister Prince Saud al-Faisal has over the past week been at the centre of diplomatic efforts to stand up to the challenge posed by IS to the status quo.
He and his counterparts from Egypt, Qatar and the Emirates held talks on Syria and "the rise of terrorist extremist ideology", according to an official statement.
They agreed on "the need to seriously work to deal with these crises and challenges to preserve security and stability in Arab countries", it said.
The Saudi minister also hosted talks with Iran's deputy foreign minister, Hossein Amir-Abdollahian, in a rare high-level encounter between the long-time rival states.
They discussed the situation in Iraq and "means to confront extremism and terrorism", an Iranian official said, without elaborating on how Riyadh and Tehran could cooperate against the jihadists.
And Prince Saud, accompanied by the kingdom's interior minister and intelligence chief, travelled to Qatar at the start of a regional tour also taking in Bahrain and the Emirates.
- Saudi-Qatar rapprochement bid -
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Gulf powerhouse Saudi Arabia and its small but wealthy neighbour Qatar, which has its own regional ambitions, have already been at odds for the past six months.
In an unprecedented step between nominal allies in the six-nation Gulf Cooperation Council (GCC), Riyadh, Abu Dhabi and Manama withdrew their ambassadors from Doha in protest at alleged interference in their affairs through Qatar's support for the Muslim Brotherhood movement.
Abdulkhaleq Abdulla, a professor of political sciences at Emirates University, said Qatar has been stepping up attempts to ease tensions with its neighbours.
"Qatar is trying to do all what it can to please Riyadh but Riyadh is still unsatisfied," he said.
With the highest religious authority in Saudi Arabia, its grand mufti, branding the IS Islam's "enemy number one", the GCC which also groups Kuwait and Oman has lined up a meeting of foreign ministers in the Saudi city of Jeddah on Saturday.
But regional expert Frederic Wehrey holds out little hope of joint Arab military action against the IS jihadists.
"The GCC does not have the capacity for real expeditionary military operations outside the Gulf," said Wehrey of the Carnegie Endowment for International Peace.
"And continued mistrust, disputes over command authority and interoperability deficiencies amongst their militaries prevent them from deploying as a real military coalition."
He doubted that any Gulf air force "could provide any real firepower complement to US air strikes beyond providing the symbolic legitimacy of an Arab state participating."
As for regional giants Iran and Saudi Arabia, their mutual hostility towards IS was unlikely to evolve into "real meaningful cooperation".
"There are too many other strategic issues that divide the two states," he said, pointing to Syria, Lebanon, Bahrain, the nuclear file and the US presence in the region.