GEOFF BENNETT: Welcome to the "News Hour."

A return to open hostilities between the U.S.

and Iran.

Late last night, U.S.

Central Command said it completed a new round of strikes against Iran.

Neither side appears ready to return to talks, and Iran has not said it will allow free passage through the Strait of Hormuz.

Our Liz Landers starts our coverage.

LIZ LANDERS: Overnight.

U.S.

airstrikes knock out a maritime control tower in Southern Iran, and a burst of orange dots the horizon.

In total, U.S.

Central Command says it struck roughly 90 targets across Iran last night, targeting military assets to -- quote -- "further degrade Iran's ability to attack commercial shipping," an uptick from the 80 targets that were hit the night before.

By day, Iran's coast billowed with plumes of fire off the water, boats set ablaze.

In retaliation, Iran fired volleys across the Gulf, targeting American military sites.

Air raid sirens echoed over Kuwait city, a missile with a message -- quote -- "To the memory of the clenched fist of the martyred leader."

Another violent night and a second cycle of bombing pulling at the seams of a cease-fire already threadbare.

DONALD TRUMP, President of the United States: We just hit them very hard.

LIZ LANDERS: And last night aboard Air Force One, little appetite for diplomacy.

DONALD TRUMP: I say we hit them 20 to 1.

Every time they hit us, we're going to hit them 20.

LIZ LANDERS: In turn, Iran made threats of its own.

Parliamentary leader Mohammad Bagher Ghalibaf warned on social media -- quote -- "America still hasn't learned that bullying and breaking promises are no longer cost-free.

Let me put it plainly.

If you strike, you will get hit."

The return to open hostilities follows Iran striking three commercial oil tankers in the Strait of Hormuz, spurring this week's round of wide-scale U.S.

strikes against the Islamic Republic.

That fighting, the U.N.

said today, is trapping over 6,000 sailors in the partially blocked waterway.

As the passage remains perilous, some of the remaining ships transiting go dark, turning off their signal before navigating.

VICE ADM.

ROBERT HARWARD (RET.

), Former CENTCOM Deputy Commander: In Afghanistan and Iraq, we had boots on the ground, which really becomes a great differentiator.

Are we willing to take that risk here?

LIZ LANDERS: Retired Vice Admiral Robert Harward was the deputy commander of CENTCOM from 2012 to 2014.

He's now a senior fellow at the Jewish institute for National Security of America.

He says sending military troops into Iran to destroy Iranian forces that threaten shipping is necessary.

VICE ADM.

ROBERT HARWARD (RET.

): If we don't know if we have completely eradicated drones and missiles from Bandar Abbas, Jask, Kharg Island, anywhere else, going in bombing it and then following it with a raid, temporary raid to put boots on the ground to ensure we have accomplished that mission is another option available to the president.

But we did it in the case of a downed pilot.

I think this is a strategic and necessary requirement to do it again now, to verify and ensure they cannot threaten the straits.

ALAN EYRE, Middle East Institute: The problem is, you put boots on the ground, they're targets.

LIZ LANDERS: Alan Eyre, former negotiator for the Iranian nuclear deal under Obama, says sending U.S.

troops into Iran would not enable the United States to eliminate Iran's ability to threaten shipping in the Strait of Hormuz.

ALAN EYRE: Iran, at least in terms of all the assessments I have seen in open-source media, has significant remaining quantities of missiles and drones, these small boats that could be quickly deployed, fast attack craft.

So even with boots on the ground, unless you're going to stay there, I don't think we could sufficiently degrade their ability to threaten maritime shipping in the strait.

LIZ LANDERS: Meantime, on the ground in Iran, the concluding steps in a weeklong march for the funeral of the late Ayatollah Ali Khamenei.

The procession reached its climax today, entombing the coffin of the Islamic Republic's former leader in his hometown, his body followed by those of his family carried by truck.

Thousands of mourners lined the streets to bid farewell and call for revenge, the final burial for the assassination that ignited the war now approaching its fifth month as a return to all-out conflict rears its head.

For the "PBS News Hour," I'm Liz Landers.