GEOFF BENNETT: Welcome to the "News Hour."

The U.S.

military said this evening it started what it calls self-defense strikes against Iran for the downing of a U.S.

Army helicopter near the Strait of Hormuz.

Earlier, on social media, President Trump said two crew members on board were both safe and uninjured, but that the U.S., as he put it, must of necessity respond to this attack.

U.S.

military officials say the Apache helicopter went down while on patrol off the coast of Oman.

The rescue was carried out by an unmanned drone boat in what appears to be a first for the U.S.

military.

In a social media post of his own, Iran's foreign minister responded by saying -- quote -- "Foreign forces in proximity to our territory are at constant risk on account of their own human errors, plain accidents, or potentially being caught in the crossfire."

He suggests that the best solution is for them to leave.

For more on this still developing story, we're joined by Dan Lamothe, who covers the U.S.

military for The Washington Post.

Dan, thanks for being with us.

CENTCOM says an investigation is under way.

What has been confirmed so far about how this helicopter went down off the coast of the Strait of Hormuz?

DAN LAMOTHE, The Washington Post: We're really waiting on additional details for how that helicopter managed to go down.

There's some question over whether or not it may be an Iranian drone that hit the helicopter, which I think may also be a first if confirmed that a drone would have taken down an American helicopter.

But we're actually in a moment now really, as we're speaking, where the United States is responding.

There's targets being hit this hour.

And we're waiting to see where exactly that leaves the whole thing after.

GEOFF BENNETT: I was going to ask you that.

What more can you share in terms of your reporting about the response?

The U.S.

-- U.S.

officials are calling it a proportional response to an unjustified Iranian aggression?

DAN LAMOTHE: Yes, that's how they're framing it.

The fact they're calling it a proportional response would lead to believe that we're probably looking at a handful of targets.

They often will try to do sort of like for like.

So, if you told me that they're, for instance, hitting launch points from where Iranian drones may be launched along the coastline, that would strike me as a likely scenario at this point.

But we're really waiting for those details in this moment.

GEOFF BENNETT: One of the striking details here is that the two airmen were recovered by this unmanned Navy vessel.

What more is known about that technology?

DAN LAMOTHE: Yes, that's a remarkable feat here, is that we have this 24-foot-long Navy vessel that really only arrived in theater back in March shortly after the war began.

That enables the United States to pick up downed pilots and other people who may be at risk in the water without putting more American forces in harm's way.

So, in this case, this vessel was able to find these Americans, take these Americans aboard, and then move to a second location, at which they were hoisted up into a helicopter and removed to a safe space then.

GEOFF BENNETT: Finally, Dan, helicopter shoot-downs are not unheard of, but they are still fairly rare.

Put this in context for us.

How unusual is it for a U.S.

military aircraft to be brought down in the way that it was?

DAN LAMOTHE: Yes, certainly, it's not a daily occurrence even in war, but, I mean, it is something that is a regular risk.

Helicopters fly low, they fly slow, they are a likely target, and they are in a range where surface-to-air missiles, drones, other things can all take these helicopters down.

So this has been a constant risk going back to Iraq, Afghanistan, Somalia.

And now we have seen it here as well.

It's remarkable that we appear to have no U.S.

fatalities here.

GEOFF BENNETT: Dan Lamothe, thanks again for sharing your reporting with us.

We appreciate it.

DAN LAMOTHE: Thank you.