Ten Arab countries have agreed to help the US in its fight against the jihadist group, Islamic State (IS).
After talks with US Secretary of State John Kerry, they pledged to provide military support and humanitarian aid, and to halt the flow of funds and foreign fighters to IS.
Mr Kerry told the BBC they recognised the danger that had been unleashed.
However, Russia warned the US against expanding its campaign of air strikes from Iraq into neighbouring Syria.
The Russian foreign ministry said any such action, without the backing of the UN Security Council, would be “an act of aggression” and a “gross violation” of international law.
US President Barack Obama has threatened action against IS – also known as Isil – and Mr Kerry has been tasked with trying to build a regional coalition against the militants.
As the meeting in Jeddah broke up, a joint communique declared a “shared commitment to stand united against the threat posed by all terrorism” including IS.
It added that participants had “discussed a strategy to destroy Isil wherever it is, including in both Iraq and Syria”.
President Obama: “We will degrade and ultimately destroy” IS
In addition to Saudi Arabia, Arab states taking part were Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Qatar and the United Arab Emirates.
“The region recognises the danger that has been unleashed and they are full-throatily ready to deal with that and that is why they committed today to take the actions they have committed to,” Mr Kerry later told the BBC.
Nato member Turkey was also at the Jeddah meeting, but did not sign the communique.
Mr Kerry downplayed the move, saying the important US ally was dealing with some “sensitive issues” but remained engaged in the campaign.
“Turkey’s very engaged and has been very involved,” he explained. “I have full expectations that we’ll work through whatever issues or questions exist.”
Turkey has reportedly been reluctant to take a prominent role in the coalition, partly out of concern for the 49 Turkish citizens being held hostage by IS.
Speaking on Wednesday, Mr Obama said any group that threatened America would “find no safe haven”. He also announced that 475 US military personnel would be sent to Iraq but would not have a combat role.
Analysis: BBC diplomatic correspondent Jonathan Marcus
This is coalition building in action. On paper, John Kerry could have wished for little more. Translating words into actions, though, may be more difficult.
In some Gulf countries there remains a modicum of sympathy for Islamic State. Iran was, of course, not present – it’s a strong competitor of Saudi Arabia’s but nonetheless a key “ally”, of a kind, in this struggle.
Holding this disparate coalition together in regard to Iraq is one thing, but countering IS in Syria may stretch it to its limits.
The possibility of air strikes brought a strong reaction from Russia – a staunch ally of embattled Syrian President Bashar al-Assad.
“This step, in the absence of a UN Security Council decision, would be an act of aggression, a gross violation of international law,” spokesman Alexander Lukashevich was quoted as saying.
Syria also repeated its warning that the US had to co-ordinate with the Syrian government before launching air strikes on its territory.
“Any action of any kind without the consent of the Syrian government would be an attack on Syria,” National Reconciliation Minister Ali Haidar said.
Last month, Syria offered to help the US fight Islamic State, however the US ruled that out.
The US has launched more than 150 air strikes against the group in Iraq and has provided arms to Iraqi and Kurdish forces fighting against IS.
The jihadist group has become notorious for its brutality, recording their beheadings of enemy soldiers and Western journalists.
BBC.
