GEOFF BENNETT: Today, Moscow announced it will not renew the yearlong deal that allowed Ukraine to export its grain through the Black Sea.

There was critical food supplies which were shipped to countries in Africa, the Middle East and Asia could now be cut off just at the moment when many vulnerable nations need them the most.

William Brangham explores the impact of this decision.

WILLIAM BRANGHAM: Geoff, the agreement, known as the Black Sea Grain Initiative, was brokered last year by the U.N. and Turkey after Russia's naval blockade of Ukrainian ports trapped millions of tons of corn, barley and wheat.

For the past year, Russian forces allowed Ukraine to ship more than 32 million metric tons of those grains through the Bosphorus Strait and on to the rest of the world.

The deal has been renewed three times, most recently in May.

Tonight was the deadline to extend the deal, but Russia announced its suspension, complaining that Western sanctions have restricted the sale of its agricultural products.

Because Ukraine is such a major producer of grain and other foodstuffs, U.N. Secretary-General Antonio Guterres today said the end of the deal could have far-reaching consequences.

ANTONIO GUTERRES, United Nations Secretary-General: Participation in these agreements is a choice, but struggling people everywhere and developing countries don't have a choice.

Hundreds of millions of people face hunger, and consumers are confronting a global cost of living crisis.

And they will pay the price.

WILLIAM BRANGHAM: For more on what this suspension might mean, we're joined again by David Miliband.

He's the president of the International Rescue Committee, a humanitarian organization that works in over 40 countries.

David Miliband, great to have you back on the program.

As you heard, Secretary-General Guterres acknowledged that participating in this deal is voluntary.

So what do you make of Russia's decision to not renew it?

DAVID MILIBAND, President, International Rescue Committee: Well, this is a callous move that has been condemned by the U.N. secretary-general for a very simple reason.

It piles agony upon risk for some of the most vulnerable communities in the world.

And the impact is twofold.

One is obvious and direct.

For example, in East Africa, one of the most stricken regions when it comes to food malnutrition and hunger, 80 percent of their grain supplies come from Russia or Ukraine.

But there's also an indirect impact which I think is very important for your viewers to understand.

That's the impact on global food prices.

We all know, in the United States or in the U.K., food inflation, food price inflation has been real, but it's twice as high, 40 percent over the last year, in countries that are most at risk of famine and malnutrition.

And given that there are 50 million people in East Africa alone who are at the highest levels of U.N. food insecurity, this is a really dark and dangerous moment for them.

WILLIAM BRANGHAM: I want to touch on those impacts in a moment.

But, first, Russia's argument is that they pulled out of this deal because it was unfair to them, that the sanctions were hurting their ability to sell their agricultural products, even though there are no sanctions, we should say, on their particular products.

One analyst we spoked to today argued that Russia's argument is not -- doesn't hold up to scrutiny.

Let's hear what she had to say.

CAITLIN WELSH, Center for Strategic and International Studies: It's important to remember that Russia is playing victim right now to a crisis of its own making.

It's actually Ukraine that is suffering to a far greater extent than Russia is right now.

Russia is simply doing what it can to stall the workings of this initiative, of the Black Sea grain initiative, that it understands that Ukraine and many other countries around the world are benefiting from, which, of course, is to Russia's own detriment in the course of this war.

WILLIAM BRANGHAM: Do you share that concern that this -- that Russia's claims are illegitimate?

DAVID MILIBAND: Well, my only concern is for the people on the receiving end of this move.

The International Rescue Committee is not a partisan or political organization.

We're a humanitarian organization.

And we speak to the real needs that we see.

We can, however, note that Russian agricultural exports have actually gone up in the last year.

And our concern has to be with the fact that this grain initiative, which is so important for the global supply and demand of critical foodstuffs, but especially important in some of the most vulnerable parts of the world, is going to hit them very hard.

There was no quid pro quo between Russian interests and humanitarian interests.

This grain deal was done on its own merits and needs to be followed through on its own merits.

WILLIAM BRANGHAM: Are there specific nations that, when you look at the at the global map and the nations that you work with, that you worry most particularly about?

I mean, we saw today that Nigeria declared a state of food emergency.

What nations stand out as most in need?

DAVID MILIBAND: Yes, that's a great point that the burden of food insecurity is not shared equally.

Those most at risk are countries suffering from conflict and from the climate crisis.

So the top five would include countries like Somalia and Ethiopia in East Africa.

They would certainly include Northeast Nigeria.

But I'd also point you to a countries like Burkina Faso in the Sahel region of Africa.

And then I'd point you towards countries like Afghanistan, where poverty is real and malnutrition is rife.

And even in the southern province of Pakistan, in Sindh Province, there's now evidence of malnutrition as well that our teams on the ground are working to tackle.

All of this isn't because there's a lack of food globally.

It's because food price inflation because of restrictions on the supply of food and interference with subsistence agriculture as a result of climate change is hitting these vulnerable communities the hardest.

WILLIAM BRANGHAM: Your organization today called on the U.N. very specifically to beef up its efforts, given the suspension of this deal.

What specifically do you want them to do?

And do you think they will heed this call?

DAVID MILIBAND: Well, I think there's two or three things that immediately come to mind.

First of all, the Russian government have in the past withdrawn from the deal and then got back -- gone back onto it.

So, clearly, step one is very active diplomacy of the kind that you have seen from the secretary-general of the U.N. speaking out today.

This needs to be resolved.

Secondly, I think it's very important to hear the voice of some of those communities who are affected.

It's the leaders of those communities and the people on the ground whose voice needs to be heard.

Thirdly, I think it's very, very important that we underline that, in the countries I have mentioned, U.N. appeals for humanitarian aid are massively underfunded.

Just to take one example, Somalia, which in some ways is the epicenter of the global food crisis, its U.N. humanitarian appeal is only 30 percent funded.

That is a recipe for the kind of malnutrition and hunger that we're seeing on the ground every day.

WILLIAM BRANGHAM: You, as -- are saying -- you run a major humanitarian organization, but many people will remember that you were the U.K.'s foreign secretary and are well-versed in global diplomacy.

What do you believe it will take to pressure Vladimir Putin to reopen the supply line?

DAVID MILIBAND: Well, you use the word pressure, and pressure is the critical element.

This is a moment for countries around the world, many of which have tried to not take sides in the course of this Ukraine conflict, to point out that there are innocent victims, not just within Ukraine, but beyond as well.

This is a moment when global voices are going to be very important, not just the obvious Western voices.

I think it's also very important that those Western governments that are criticizing the Russian move put their money where their mouth is and start fulfilling the pledges that are so much needed to meet those humanitarian funding appeals that are at the moment not being properly heeded.

WILLIAM BRANGHAM: David Miliband of the International Rescue Committee, thank you so much for your time.

DAVID MILIBAND: Thank you so much for having me again.