RIYADH (Reuters) - The United States will work with Gulf Arab nations to strengthen their shared defenses against threats including Iran, U.S. Secretary of State Hillary Clinton said on Saturday.

Speculation about Tehran’s nuclear ambitions is a source of anxiety among Sunni-led Gulf Arab states, for whom Shi’ite Iran has long been a regional rival.

“The commitment of the United States to the people and the nations of the Gulf is rock-solid and unwavering. Our strong bilateral relationships are a rock of stability in the region,” Clinton said in prepared remarks delivered in the inaugural meeting of a new U.S.-Gulf security forum.

“Now we look forward to expanding our multilateral cooperation as well,” she said at the opening of the meeting with foreign ministers from the Gulf Cooperation Council, which includes six Gulf countries.

Clinton said Saturday’s discussions with Gulf foreign ministers would include the political change that has swept the Middle East in the past year and the violence in Syria, in addition to Iran’s disputed nuclear program “and curbing its interference in the affairs of its neighbors”.

Gulf Arab states have accused Iran of backing an uprising in Bahrain, and of fomenting unrest among the Shi’ite Muslim minority in mostly Sunni Saudi Arabia.

Fresh talks between Iran and world powers are expected to get underway in mid-April as Tehran faces increasing economic and political pressure over its nuclear activities.

Western diplomats and analysts say that getting Iran to stop the higher-level uranium enrichment it started two years ago and has since sharply increased will be a priority in next month’s talks - the latest bid to avert the threat of Israeli air strikes on Iranian nuclear sites.

On Friday, U.S. President Barack Obama vowed to forge ahead with tough sanctions on Iran, saying there was enough oil in the world market to allow countries to cut Iranian imports.

Iran says it has a sovereign right to peaceful nuclear technology and has repeatedly rejected U.N. resolutions calling for a suspension of all uranium enrichment.

Tehran denies it is pursuing a nuclear weapon or has meddled in affairs of its neighbors.

U.S. officials have said the United States is hoping to enhance its cooperation across the Gulf region on fighting piracy and violent extremism.

It also hopes to help Gulf nations enhance their missile defense capabilities, including U.S. arms sales.

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Oil supplies have also been a focus of Clinton’s visit to the Gulf kingdom, which is the world’s top oil exporter.

The United States and other consumer countries fear Saudi Arabia may cut oil output if they release emergency reserves, neutralizing their effort to cool world energy markets.

A U.S. official said that Clinton discussed Saudi Arabia’s ‘essential’ role in maintaining strong global oil supplies during a meeting with Saudi King Abdullah on Friday.