SAudi Arabian officials are warning that they will seek to match Iran’s nuclear arsenal, a US newspaper reported Thursday, as US President Barack Obama and leaders from six Gulf nations — including Riyadh — convened outside Washington to work through tensions sparked by the US bid for a nuclear deal with Tehran, a pursuit that has put regional partners on edge.

Along with Saudi Arabia, smaller Arab countries also say they also plan to pursue a nuclear weapons program to offset Iran’s, portending a much-feared nuclear arms race in the Middle East, according to the New York Times.

“We can’t sit back and be nowhere as Iran is allowed to retain much of its capability and amass its research,” one Arab leader attending the Camp David summit told theNew York Times.

The official, who was unnamed, said he and others will also make their case to Obama at the meeting Thursday.

Obama is seeking to reassure the Gulf leaders gathering at Camp David that US overtures to Iran will not come at the expense of commitments to their security. He is expected to offer them more military assistance, including increased joint exercises and coordination on ballistic missile systems.

Obama and the leaders from Saudi Arabia, Qatar, United Arab Emirates, Kuwait, Oman and Bahrain opened their talks with a private dinner Wednesday night at the White House. Just two heads of state are among those meeting Obama, with other nations sending lower-level but still influential representatives.

Arab and Israeli officials have lobbied against the deal, though Gulf states have kept their criticism more discreet. Yet leaders around the region have warned that Iranian nuclear development will lead them to also pursue nuclear programs of their own, a worrying idea in a part of the world already riven by violent conflicts.

“Whatever the Iranians have, we will have, too,” former Saudi intelligence head Prince Turki bin Faisal said last month at a special session of the Asan Plenum, a conference held by the South Korean-based Asan Institute for Policy Studies, according to the New York Times.

Faisal also warned that the Iranian nuclear deal “opens the door to nuclear proliferation, not closes it, as was the initial intention.”

When Thursday’s meetings at the presidential retreat in the Maryland mountains conclude, it’s unlikely Obama will have fully assuaged the Gulf’s deep-seated fear of Iranian meddling in the region.

“My guess is that the summit is going to leave everybody feeling a little bit unsatisfied,” said Jon Alterman, the Middle East director at the Center for Strategic and International Studies.

The most notable absence from the meeting is Saudi King Salman. On Sunday, Saudi Arabia announced that the king was skipping the summit, just two days after the White House said he was coming.

Crown Prince Mohammed bin Nayef and Deputy Crown Prince Mohammed bin Salman were representing Saudi Arabia instead. They held a separate meeting with Obama before the other leaders arrived.

The president made no mention of Saudi skepticism of the Iran talks as he opened the meeting, but acknowledged the region is in the midst of a “very challenging time.”

The White House and Saudi officials insist the king is not snubbing Obama. But Salman’s conspicuous absence comes amid indisputable signs of strain in the long relationship between the US and Saudi Arabia, driven not only by Obama’s Iran overtures, but also the rise of Islamic State militants and a lessening US dependency on Saudi oil.

“There have been disagreements under this administration and under the previous administration about certain policies and development in the Middle East, but I think on a set of core interests, we continue to have a common view about what we aim to achieve,” said Ben Rhodes, Obama’s deputy national security adviser.

The Gulf summit comes as the US and five other nations work to reach an agreement with Iran by the end of June to curb its nuclear ambitions in exchange for relief from international economic sanctions. The Gulf nations fear that an influx of cash will only facilitate what they see as Iran’s aggression.

The White House says a nuclear accord could clear the way for more productive discussions with Iran about its reputed terror links. The US has criticized Iran’s support for Hezbollah, as well as terror attacks carried out by Iran’s Quds Force.

In 2011, the Obama administration accused Iran of plotting to kill the Saudi ambassador to the United States in Washington.

The Saudis are also particularly concerned about the situation in Yemen, where Houthi rebels with ties with Iran have ousted the US- and Saudi-backed leader.

For more than a month, a Saudi-led coalition has tried to push back the Houthis with a relentless bombing campaign. On Tuesday, a five-day humanitarian ceasefire went into effect, though the pause in fighting was already at risk. A jet fighter from the Saudi coalition on Wednesday struck a military convoy belonging to Shiite rebels and their allies in southern Yemen.

Saudi officials cited the ceasefire as one of the reasons why King Salman needed to stay in Riyadh and not make the trip to the United States.

The Saudi king isn’t the only head of state sending a lower-level representative to the summit. The heads of the United Arab Emirates and Oman have had health problems and were not making the trip.

Bahrain’s royal court announced Wednesday that rather than travel to Washington, King Hamad bin Isa Al Khalifa would be attending a horse show and meeting with Queen Elizabeth II.