A potential diplomatic agreement between the United States and Iran would be virtually unfeasible if Tehran were to proceed with imposing a toll system in the Strait of Hormuz, US Secretary of State Marco Rubio has warned.

At the same time, the Secretary of State expressed hope that the visit of Pakistan’s army chief to Iran would help de-escalate tensions and advance diplomatic efforts to end the conflict, noting that there are signs of progress in the process.

“I believe the Pakistanis will go to Tehran today. Hopefully that will move things forward,” he told reporters.

In more critical remarks, Rubio also targeted NATO member states, accusing them of “refusing to do anything” to support the United States in its confrontation with Iran.

Shortly before departing for Sweden, where he is due to attend the NATO foreign ministers’ meeting, he said that President Donald Trump “is not asking for troops or fighter jets to be sent,” but argued that some allies are avoiding any contribution, adding: “This has been very disturbing to us.”