GEOFF BENNETT: Our Nick Schifrin is back with us now with breaking developments out of Iran, where the U.S.

conducted new strikes in response to what President Trump said was Iran's violation of the cease-fire.

Nick, what more can you tell us?

NICK SCHIFRIN: Geoff, a U.S.

official tells me tonight that six U.S.

aircraft attacked four Iranian targets, Iranian radar installations, as well as missile and drone storage in Sirik on the Strait of Hormuz.

Now, the military calls the strikes a response to an Iranian attack yesterday on the container ship Ever Lovely south of Sirik off Oman's coast.

You see it, the red dot right there.

And now, tonight, Iran vowing another response that in their words would be swift and decisive.

GEOFF BENNETT: So does this threaten to derail the effort at U.S.

and Iran diplomacy?

NICK SCHIFRIN: I mean, the memorandum of understanding says hostilities will stop.

So the more military action you get, clearly, the more that challenges diplomacy.

Iran called tonight's action a reckless violation of the cease-fire.

The U.S.

says Iran violated the cease-fire by attacking that ship.

But there's a bigger problem here, Geoff.

Iran is trying to maintain its choke hold on the strait, not only by attacking that ship yesterday, but also demanding that other ships use a route through the strait close to its border in the north, that's in orange there, instead of the route the U.S.

wants near Oman.

That route is in yellow.

So President Trump's trying to use these military strikes tonight to convince Iran to open the strait once and for all, as President Trump warned that he would.

But it is not clear if it's enough.

It's not clear if Iran is even interested in giving up the leverage that it has gained during the war, which is that -- its ability to open and close the strait whenever it wants.

Tonight, just now, Vice President Vance sent a message, look, if Iran has a problem -- quote -- "Pick up the phone," but -- quote -- "Violence will be met with more violence."

GEOFF BENNETT: All right, Nick Schifrin, thanks, as always.

NICK SCHIFRIN: Thank you.