(CNN)— US officials said Washington expects Tehran to issue a public statement in the coming days affirming that the Strait of Hormuz is open and that commercial ships attempting to cross the waterway will not be attacked.

A senior US official said that if safe passage through the strait, which has seen a sharp decline in traffic again, is not guaranteed, the two sides will 'never move' to the stage of negotiations on nuclear weapons.

The US official added in a call with reporters on Friday: 'What you are seeing is, in some respects, a manifestation of the power struggle taking place inside Iran at the moment.'

Officials declined to specify the consequences Iran might face if it does not issue such a public statement, but they warned, in general, that the United States may take additional actions.

The strait, located between Iran and Oman where their exclusive economic zones meet in the middle, has emerged as a major obstacle to a ceasefire; Iran continues to assert control over parts of the waterway, and opened fire on ships earlier this week. In response, the United States launched a series of military strikes lasting days against Iranian targets.