CENTCOM said it will block all traffic 'entering and exiting Iranian ports.'
President Donald Trump announced "major combat operations" against Iran on Feb. 28, with massive joint U.S.-Israeli strikes targeting military and government sites.
Trump set a deadline for Iran to fully reopen the Strait of Hormuz or face broad strikes on its critical infrastructure. Hours before the deadline expired, Trump said he had agreed to suspend planned bombing for two weeks if Iran agreed to reopen the Strait of Hormuz.
Iranian Foreign Minister Abbas Araghchi then said that "safe passage through the Strait of Hormuz will be possible via coordination with Iran's Armed Forces and with due consideration of technical limitations."
Israeli Prime Minister Benjamin Netanyahu said he supported the ceasefire with Iran, but that Lebanon -- where intense Israeli strikes continued -- was not covered by the agreement, despite Iranian protests.
When asked by reporters if he expected Iran to come to the negotiating table, Secretary of State Marco Rubio said "hope we have more news later today on that."
"The whole world's been impacted, unfortunately, because Iran is violating every law known by striking commercial vessels in the Strait of Hormuz, and it's a big problem for the world," he said.
The White House is responding to reports that Iranian officials have reportedly stopped negotiations with the U.S. ahead of President Donald Trump's 8:00 p.m. deadline, telling ABC News that the "only the president knows where things stand."
"The Iranian regime has until 8 p.m. Eastern Time to meet the moment and make a deal with the United States. Only the President knows where things stand and what he will do," White House press secretary Karoline Leavitt said in a statement.
President Donald Trump told Fox News on Tuesday that the strikes on Iran that he promised would begin at 8:00 p.m. Tuesday are "happening," but cautioned that things "could change."
Trump's comments come just hours after the president said "a whole civilization will die tonight never to be brought back again" if a deal was not reached between the U.S. and Iran.
Trump told Fox News that if negotiations were successful then plans for strikes could change, but confirmed that the U.S. was preparing for his deadline.
Russia and China have vetoed a U.N. Security Council resolution aimed at reopening the Strait of Hormuz.
The resolution, sponsored by Bahrain, had been repeatedly watered down because of opposition from Russia and China.
The vote took place just hours before an 8 p.m. Eastern time deadline set by U.S. President Donald Trump for Iran to open the strategic waterway or face attacks on its power plants and bridges.
One-fifth of the world's oil typically passes through the strait, and Iran's stranglehold during the war has sent energy prices soaring.
