Saudi Arabia's King Salman opened a Gulf Arab summit on Tuesday by calling for regional unity to confront Iran and secure energy supplies and maritime channels.
"Our region today is passing through circumstances and challenges that require concerted efforts to confront them as the Iranian regime continues its aggressive actions that threaten security and stability...," he said.
Iran and Saudi Arabia have been regional rivals for years, especially after Iran began expanding its influence in the region by supporting Syrian strongman Bashar Assad, the Houthis in Yemen and building proxy forces in Iraq.
In a televised speech, King Salman also urged the global community to address Iran's nuclear and ballistic missile programs.
Tensions between the two sides soared after US sanctions cut off Iran's oil exports in May. Suspicious attacks on oil tankers in the Persian Gulf region was blamed on Iran.
In September, a sophisticated missile and drone attack destroyed oil installations in Saudi Arabia. The United States, European powers and Saudis blamed Iran, which insists Houthis were responsible.
Saudi Arabia tries to maintain a Sunni front against Shiite Iran in the region.
Qatar's prime minister attended the summit in Saudi Arabia on Tuesday in the most concrete sign yet of a possible thaw in a regional dispute, but the meeting ended without public mention of the 2-1/2 year row.
Qatar has maintained cordial relations with Iran, angering Saudis and their allies.