US President Barack Obama speaks following his participation in the summit of the Gulf Cooperation Council (GCC) in Riyadh, Saudi Arabia, April 21, 2016

US President Barack Obama on Wednesday defended the Iran nuclear deal his administration had long lobbied for, but also pledged vigilance against Tehran at a summit attended by Gulf leaders in the Saudi capital Riyadh.

“We will remain vigilant to make sure Iran fulfills its commitments, just as we fulfill ours,” Obama said at the close of the meeting with the six-nation Gulf Cooperation Council (GCC).

Obama’s administration lent its weight for the deal, signed in July last year with the Islamic republic and six world powers, to use diplomacy in order to block pathways for Iran to develop a nuclear arm, an allegation Tehran has long rejected.

Gulf states have long expressed concerns over Iran’s interference and meddling in the region, a worry Obama has tackled in his Riyadh visit when he said Iran must be held “accountable” and that the US is going to work to stop Iran from backing the Houthi militia group in Yemen.

Need for talks

However, he said there is a need for a “dialogue” as well, highlighting his administration’s keenness for diplomacy.

Citing Iran’s “destabilizing activities” in the region, he said: “Even with the nuclear deal we recognize collectively that we continue to have serious concerns about Iranian behavior.”

But he added: “None of our nations have an interest in conflict with Iran.”

While concerns remain over Iran and economic issues, including the collapsed oil prices, he also described the GCC monarchies as united in their commitment to defeating ISIS and soothing other regional conflicts.

“We remain united in our fight to destroy ISIL,” he said, using another acronym for ISIS, at the close of the summit.

Obama, finishing his brief trip to the kingdom, said he and the Gulf leaders had agreed about ways to move forward in campaign against ISIS, with members of the GCC states agreeing to “increase their contributions to the fight.”

He also said “the United States and the GCC will launch a new high-level economic dialogue with a focus on adjusting to lower oil prices, increasing our economic ties and supporting GCC reforms as they work to provide jobs and opportunities to their young people and all of their citizens.”

Iraq, Syria

He said the nations had also agreed to help Iraq. That was a nod to Obama’s request to Gulf countries to step up their financial and political support for rebuilding Iraq after years of war.

Obama’s comments in the Saudi capital came after talks aimed at reassuring and coordinating with Mideast allies that harbor serious doubts about Obama’s outreach to Iran and about US policy toward Syria, where a civil war rages on.

Obama said the fragile cessation of hostilities there was under “tremendous strain” and he decried continued violations, but made the case for sticking to the US strategy of using diplomatic talks to pursuing a political transition for Syria.

“This violence is yet another reminder that there’s just one way to end this civil war,” Obama said, adding that the Gulf leaders had agreed.

The summit followed bilateral talks that Obama held with Saudi King Salman on Wednesday shortly after arriving in the kingdom. Besides Saudi Arabia, the GCC includes the United Arab Emirates, Qatar, Kuwait, Oman and Bahrain.

Saudi Arabia, the UAE and other Gulf countries share the US view that ISIS militants pose a threat, and have joined the US-led bombing campaign against the group. But they want the US to do more to attempt to remove Syrian President Bashar al-Assad from power.

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