DUBAI - Saudi Foreign Minister Adel al-Jubeir said a summit between Arab Gulf leaders and United States President Barack Obama later this week will focus on Iran's "aggressive" moves in the region, Saudi state news agency SPA reported."We see Iranian support for terrorist organizations and facilitating the work of terrorist organizations, so the challenge will be in how to coordinate US-Gulf efforts in order to collectively face these aggressive moves on the part of Iran," al-Jubeir said on Monday, according to SPA.Displeased with Washington's dealings with Iran, with an emerging deal over its nuclear program and with US security proposals to Gulf Arab nations, Saudi Arabia's King Salman will skip a major summit in Washington this week, as will the leaders of three other Gulf nations.The summit— at the White House and Camp David on Wednesday and Thursday— was organized with the very purpose of assuaging Gulf concerns with shifting US policy in the Middle East toward cooperation with Iran. In meetings just last week in Riyadh and Paris, Salman and his deputies had assured US Secretary of State John Kerry of his attendance at the summit, prompting a public White House announcement to that effect over the weekend.The White House said on Monday that Salman had confirmed his attendance before pulling out, for reasons, they said, entirely unrelated to the contents of the summit. Privately, White House officials acknowledge unresolved tensions with Riyadh over an emerging nuclear deal with Iran, which seeks to cap, restrict, monitor and partially roll back Tehran's nuclear work for a finite period in exchange for sanctions relief. Concerned the deal with empower Iran and its activities across the region, Saudi Arabia and its allies in the Gulf Cooperation Council are seeking concrete security guarantees that will guard against Iranian aggression. Days before the summit, all but two leaders, the emirs of Qatar and Kuwait, had declined the president's invitation. Oman's prime minister and crown princes from the UAE, Bahrain, Kuwait and Saudi will all attend in their leaders' steadMichael Wilner contributed to this report.