This is NBC Nightly News with Jose Diaz-Belard.

Good evening. We begin tonight with a stunning reversal that could derail the push to end the war with Iran.

Today, Iran declared the Strait of Hormuz closed, just a day after, saying it was completely open.

Iran's Revolutionary Guard blaming the U.S. for its ongoing naval blockade.

We also saw chaos in the strait today.

Iranian forces allegedly shooting at this Indian oil tanker.

Speaking to reporters at the White House today, President Trump appeared optimistic.

But there are growing questions tonight about whether a peace deal is possible right now.

We have two reports tonight, starting with Raf Sanchez.

Tonight, chaos in the Strait of Hormuz, Iran declaring the critical waterway shut once again,

and allegedly opening fire on two ships passing through.

A startling reversal, less than 24 hours after it declared the strait completely open,

sending oil prices tumbling and waves of relief worldwide.

They wanted to close up the strait again, you know, as they've been doing for years,

and they can't blackmail us.

Iran's Revolutionary Guard says it's a response to the U.S. maintaining its naval blockade,

which is stopping ships sailing in or out of Iranian ports, calling it a violation of ceasefire agreements.

Central Command says the blockade continues,

posting footage of troops practicing an airborne landing onto a ship.

While Iran's forces today firing near this Indian oil tank are approaching the straight,

according to state media. You can hear the tanker

crew frantically calling on them to stop the shooting. SEPA Navy, this is Motadangasan Marrador.

...