TEHRAN- Even before the NATO summit kicked off on Tuesday in Vilnius, the Lithuanian capital, there was a grave issue at hand.

Just days earlier, the United States announced it would be sending cluster munitions to Ukraine to fight Russian forces in the war. 

Washington's decision to ship the widely banned munitions was met with criticism from many around the world.

Even close U.S. allies such as the United Kingdom, Germany, Canada, New Zealand and Spain expressed concern at the U.S. move. 

More than 120 countries have signed up to the Convention on Cluster Munitions, which prohibits the production or use of the weapons and discourages their use.

New Zealand's Prime Minister Chris Hipkins denounced the move, saying the weapons were "indiscriminate, they cause huge damage to innocent people, potentially, and they can have a long-lasting effect as well". 

The U.S. Cluster Munition Coalition, which is part of an international civil society campaign working to eradicate the weapons, said they would cause "greater suffering, today and for decades to come".

Many global NGOs and other rights groups have echoed those remarks. 

The White House argues the munitions will be used by the Ukrainian military in its counter-offensive against Russian forces in the country's east. 

This means Ukraine would be firing the bombs in its own territory, and its own citizens will be the ones to suffer for decades to come.  

It's been about half a century since the CIA, in its attempt to destroy communist supply lines between Laos and Vietnam, stopped bombing Laos, after dropping tons of cluster munitions as part of the wider Vietnam War. 

Today, 50 years later, civilians who were unborn at the time are still paying the price. More than 20,000 people have been killed from unexploded cluster ordances. But no one knows the true number. 

The most affected areas near the southern border with Vietnam are also the most economically deprived regions; and 30 percent of the U.S. bombs are still undetonated, according to specialists with the Laotian military. 

This is how indiscriminate cluster munitions are. 

They shower up to hundreds of smaller bomblets, many the size of a tennis ball, over a wider civilian area. And civilians are the ones who continue to die decades later, as too many of the smaller bomblets fail to explode. 

Over the past two decades, the U.S. has used cluster munitions in the early stages of its invasions of Afghanistan and Iraq. Israel has also used the highly controversial weapons in the besieged Gaza Strip.

It's the civilians that are paying the price today in these two countries as well as in Gaza, and they will continue to suffer for many years to come, in particular children who mistake them for toys. 

"It would be the greatest danger for Ukrainians for many years or up to a hundred years if cluster bombs are used in Russian-occupied areas in the territory of Ukraine," Cambodian Prime Minister Samdech Techo Hun Sen said in a social media post, calling on Ukraine not to use them.

Cambodia is also on the dark U.S. list, where it has been bombed with cluster munitions by the American military.

In the case of Ukraine, where the counter-offensive is occurring in the country's east, it will be the ethnic Russians, who populate that region, who will continue to suffer and die for decades to come.

Ukraine is running out of arms in its counter-offensive, which many military experts say is making no effective advancements. It may heavily rely on cluster munitions because they are also effective in combating ground forces who are dug-in, which the Russian forces are. 
However effective the cluster munitions will be, it remains to be seen. Ukrainian forces are using more advanced weapons at the expense of thorough training to use sophisticated Western weaponry.

As always, it will be the Ukrainian civilians that will pay the cost in the long-term. President Joe Biden said he made a "difficult decision" in agreeing to send the controversial weapons. These are essentially weapons of mass destruction, just like chemical weapons. 

Washington's decision prompted condemnation from the United Nations and other international organizations.

"Cluster munition scatter small bomblets over a wide area," said Marta Hurtado, spokesperson for the Office of the United Nations High Commissioner for Human Rights in Geneva. "They kill and maim people years later after the end of a conflict," Hurtado warned.
The International Committee of the Red Cross said that due to weather and other environmental factors, cluster munitions can fall often outside of the intended target range. 

In a report, Human Rights Watch said that "transferring these weapons would inevitably cause long-term suffering for civilians and undermine the international opprobrium of their use."

The rights group labeled the U.S. decision as "devastating."

Other humanitarian groups have said the same. 

U.S. allies in NATO, who always take a united stance toward White House announcements, have publicly objected to Washington's decision. Even U.S. lawmakers have called Biden's move "unnecessary and a terrible mistake."  

Some have argued it would give other countries to use them in battle. 
The Russian embassy in Washington says the U.S. has, de facto, confessed to committing war crimes.

"We have taken note of the Director for Strategic Communications of the NSC John Kirby’s statements about the provision of cluster munitions to Ukraine. The official de facto confessed to the United States committing war crimes during the Ukrainian conflict. He overtly stated that civilians would fall victim to [the U.S.’] cluster-type weapons," the embassy stated.

"The United States is ready to destroy life far from its own borders with the hands of Ukrainians," the Russian diplomatic mission added.

There are also strong divisions among NATO members about Ukraine's membership, with some expressing their strong opposition to the idea. 

Europe would be the first to face “catastrophic consequences” should the war in Ukraine escalate, a Russian diplomat told state news agency RIA on Tuesday.

The remarks came as NATO leaders have gathered in Lithuania for the summit expected to result in a clearer pathway to membership for Ukraine, something Russia warned it was trying to prevent before launching a military operation against its neighbor last year, citing NATO's eastward military expansion to its borders. 

So as members of the U.S.-led military alliance stand shoulder to shoulder for a family photo in Vilnius, trying to put on a smile for the cameras, there is a strong sense of unease at where Washington is heading with its war in Ukraine.