They see an opportunity in what they regard as President Donald Trump's reluctance to become deeply entangled in another Middle East conflict ahead of November's midterm elections.
"The Iranians...believe that by widening the war and increasing the pressure, he will eventually give in," the Gulf source said. "Trump thinks he can hit the Iranians hard and bring them to the negotiating table, but they won't bend."
That calculation underpins Tehran's negotiating strategy.
Trump said talks with Iran would take place on Monday after earlier saying he had called off an imminent attack in hopes of securing a deal to reopen the Strait of Hormuz. Tehran, however, said it was not currently holding talks with the United States.
A senior Iranian source said Tehran's leadership has concluded that earlier attempts at flexibility only yielded greater pressure from Washington, reinforcing the view that leverage must be established before meaningful negotiations can begin.
In Tehran's assessment, the source said, Trump interprets concessions as weakness and responds only to pressure.
Michael Singh, senior fellow at the Washington Institute, said Tehran believes it still holds the initiative, partly because the Trump administration appears uncertain how far it is willing to go militarily.
"The Iranians are trying to press their advantage," he added. "They're interested in establishing sovereignty over the strait and exercising selective control over the waterway."
Alan Eyre, a former U.S. diplomat and Iran expert, said Tehran is pursuing a strategy of deterrence aimed at forcing Washington to lift its blockade and halt military strikes. "They don't want the U.S. to dictate the pace of events," he said.
At the centre of the dispute is the future governance of Hormuz. Oman has presented Iran with a Gulf-backed proposal for managing the waterway, including voluntary user fees, according to regional sources.
Tehran, however, is seeking administrative authority over the strait and the ability to levy service charges on vessels. Washington has rejected any fees, insisting Hormuz remain an international waterway free from Iranian control.