Saudi Crown Prince Mohammed bin Salman subsequently spoke with Trump, urging him to delay military action, return to negotiations, secure a ceasefire and pursue a diplomatic settlement, the senior diplomat and Gulf sources said.
The warning was intended for every Gulf state, another Gulf source said, but was conveyed primarily through Saudi Arabia and Qatar. Iran has in recent years repaired ties with its Gulf neighbours, including former regional rival Saudi Arabia.
Qatar, Oman and Saudi Arabia have all urged Washington to resume talks with Tehran and avert renewed conflict amid Iranian warnings that another round of U.S. strikes could "turn the region into a fireball", the second Iranian official said.
On August 2, Trump said he agreed to cancel the attack on Iran "subject to being able to rapidly make a deal".
"Saudi Arabia believes further escalation will only bring more destruction," the first Gulf source said. "That is why it urged Trump to give diplomacy a chance."
While urging Washington to pursue diplomacy, Riyadh also made clear it would defend itself if threatened. The second Gulf source said Saudi Arabia warned that any attack on its territory would be met with a military response.
Ali Shihabi, a Saudi analyst close to the Royal Court, said the kingdom’s assessment is that further escalation is unlikely to achieve the desired result. "The Kingdom believes a combination of proportionate military responses and sustained pressure on Iran in the Strait of Hormuz offers the strongest path toward a practical diplomatic settlement,” Shihabi said.
Iran's clerical leadership has repeatedly demanded the closure of U.S. military bases in the Gulf and called on Gulf Arab states to stop sharing intelligence with Washington, which Tehran believes has been used to facilitate attacks against it.
"They still remember Saudi Arabia's Aramco," he added, referring to the September 2019 drone and missile attacks on the Abqaiq and Khurais facilities that temporarily knocked out more than half the kingdom's crude oil production and exposed the vulnerability of Gulf energy infrastructure.
"The enemy continues to threaten Iranian infrastructure. If Iran suffers damage, it will inflict far greater damage in return,” added the Iranian official who cited the target list including power grids and refineries.
From Tehran's perspective, Trump now faces two unpalatable choices, the senior Iranian official said: escalate a conflict that could engulf the Gulf and disrupt global energy supplies, or accept a negotiated outcome that falls short of the decisive victory Washington seeks.
One of the principal obstacles to an agreement, the senior regional diplomat said, is Washington's reluctance to allow Tehran to emerge claiming victory.
"The United States wants something it can present as proof that it won the war," the diplomat said.