Hormuz ship traffic sinks to 3-month low as Iran disputes Trump

Both sides have hardened their negotiating positions. Iran's Supreme National Security Council laid out sweeping conditions over the weekend for reopening the strait, including an end to the U.S. naval blockade, sanctions relief, American troop withdrawals and war reparations.

Mohammad Reza Naqdi, a top advisor to the commander of Iran's Islamic Revolutionary Guard Corps, told PBS in an interview stateside Tuesday that "victory is on our side" and that "we have also seen how the American military is weaker than what we perceived." He described Washington's shifting objectives over the course of the conflict, including plans to invade Kharg Island and open the strait. "We saw confusion and bewilderment in America. It became a war without a strategy. Every two or three days, they announced a new objective," Naqdi said.

When asked whether the plan was to drag the conflict out until Trump leaves office, Naqdi said the goal was for Iran to "attain deterrence." Prolonging the conflict and causing attrition, he said, would create a cost structure for anyone considering an attack on Iran.

Kpler's data showed traffic through the strait has not recovered since late May. The 90% drop in ship movements has disrupted crude oil shipments, containerised goods and LNG flows through the chokepoint that handles about 20% of the world's oil supply.

– CNBC's Spencer Kimball and Deena Zaidi contributed to this report.