“They are going to have to make a decision. Either they are going to have to really tighten their belt and keep tightening, because it's going to get worse,” Petraeus said on ABC’s “This Week.” "There are going to be further screws tightening down in maximum pressure campaign and try to grit their teeth and get to November 2020 in hopes that their desired outcome emerges."
He added: “They're going to have to be very careful not to overplay their hand and result in some kind of response that is quite punitive.”
The Trump administration recently sent an aircraft carrier and other military resources to the Persian Gulf region, and withdrew nonessential personnel from Iraq, raising alarm among Democrats and some Republicans on Capitol Hill over the possibility of a confrontation with Iran.
Trump in recent days has downplayed any potential for conflict. But questions remain about what prompted the actions, and many lawmakers have demanded more information.
Much of the tension between Tehran and Washington stems from reports of bombings and attacks across the region that have been linked to Iranian-backed terror groups and also the U.S. withdrawal from the nuclear accord with Iran just over a year ago.
Trump pulled out of the agreement, which he has criticized as "the worst deal in history." He said the accord should have restrained Iran's ballistic missile program and curbed what his administration considers Tehran's hostile activities in the region.
The administration reimposed crippling economic sanctions on Iran that had been lifted under the agreement.
Iran retaliated by threatening to enrich its uranium stockpile closer to weapons-grade levels in 60 days if world powers fail to negotiate new terms for its 2015 nuclear deal. Iran has stopped its sale of excess uranium and heavy water as a first step — something required under the deal.
The Associated Press contributed to this report.