Rubio said Iran would not be allowed to charge Strait of Hormuz tolls.
President Donald Trump announced "major combat operations" against Iran on Feb. 28, with massive joint U.S.-Israeli strikes targeting military, government and infrastructure sites.
Following the announcement of a two-week ceasefire, initial U.S.-Iran talks in Pakistan earlier this month failed to reach a peace deal.
Trump later announced the open-ended extension of the ceasefire and the continuation of the blockade until Iran's proposal is submitted and discussions are concluded "one way or the other."
Pakistani Prime Minister Shehbaz Sharif thanked President Donald Trump for extending the ceasefire "to allow ongoing diplomatic efforts to take their course."
He called on both sides to continue to observe the ceasefire and said Pakistan will "continue its earnest efforts for negotiated settlement of conflict."
According to a White House official, Vice President JD Vance won't be traveling to Pakistan on Tuesday.
"In light of President Trump's TRUTH Social post confirming the United States is awaiting a unified proposal from the Iranians, the trip to Pakistan will not be happening today," the official said. "Any further updates on in-person meetings will be announced by the White House."
-ABC News' Emily Chang
The Iran-backed Lebanese militant group Hezbollah said it fired rockets and drones at Israeli forces on Tuesday for the first time since a 10-day truce took effect Friday "in response to the blatant and documented violations" by Israel.
The alleged violations included "attacks on civilians and the destruction of their homes and villages in southern Lebanon," Hezbollah said in a statement.
The Israel Defense Forces said it responded by striking Hezbollah's rocket launcher.
"The launches constitute a blatant violation of the ceasefire agreement," the IDF said.
President Donald Trump announced Tuesday he will indefinitely extend the current ceasefire with Iran and continue a U.S. naval blockade of the Strait of Hormuz as talks continue.
Trump said in a social media post that Pakistani mediators have asked the U.S. to "hold our Attack" until Iranian officials "can come up with a unified proposal."
"I have therefore directed our Military to continue the Blockade and, in all other respects, remain ready and able, and will therefore extend the Ceasefire until such time as their proposal is submitted, and discussions are concluded, one way or the other," Trump continued.
This comes hours after Trump told CNBC he did not want to extend the ceasefire and threatened continued bombing. He also said Iran had no choice but to accept a deal.
