Washington. The United States has agreed to provide Ukraine with controversial cluster munitions which have been banned in many countries because they left unexploded rounds, which often litter battlefields and populated civilian areas, causing unintended deaths.  

President Joe Biden said on Friday the “difficult decision” was made because "the Ukrainians are running out of ammunition” and the cluster bombs will provide a temporary fix to help stop Russian tanks.

The decision comes on the eve of the NATO summit in Lithuania, where Biden is likely to face questions from allies on why the US would send a weapon into Ukraine that more than two-thirds of alliance members have banned because it has a track record for causing many civilian casualties.

“It took me a while to be convinced to do it,” said Biden in a CNN interview. 

The move was met with divided reactions from Congress, as some Democrats criticized the plan while some Republicans backed it. It was hailed on Twitter by Ukrainian President Volodymyr Zelenskyy, who thanked Biden for “a timely, broad and much-needed defense aid package” that will “bring Ukraine closer to victory over the enemy, and democracy to victory over dictatorship.”

The munitions — which are bombs that open in the air and release scores of smaller bomblets — are seen by the US as a way to get Kyiv critically needed ammunition to help bolster its offensive and push through the Russian front lines. U.S. leaders debated the thorny issue for months, before Biden made the final decision this week.

U.S. national security adviser Jake Sullivan said the U.S. will send a version of the munition that has a reduced “dud rate,” meaning fewer of the smaller bomblets fail to explode. US officials have said Washington will provide thousands of the rounds, but provided no specific numbers.

“We recognize the cluster munitions create a risk of civilian harm from unexploded ordnance,” Sullivan told a White House briefing. “This is why we’ve deferred the decision for as long as we could. But there is also a massive risk of civilian harm if Russian troops and tanks roll over Ukrainian positions and take more Ukrainian territory and subjugate more Ukrainian civilians, because Ukraine does not have enough artillery. That is intolerable to us.”

But Marta Hurtado, speaking for the UN human rights office, said Friday “the use of such munitions should stop immediately and not be used in any place.”

UN deputy spokesman Farhan Haq said Secretary-General Antonio Guterres “wants countries to abide by the terms of that convention and so as a result, of course, he does not want there to be continued use of cluster munitions on the battlefield.”

Colin Kahl, the undersecretary of defense for policy, said the US will give Ukraine the most modern cluster munitions that have far lower dud rates. He said the bombs have been tested five times between 1998 and 2020, and the U.S. is confident the rate of unexploded duds is below 2.35 percent. While he declined to say how many the U.S. will send now, he said the U.S. has “hundreds of thousands” of cluster munitions available for Ukraine at the low dud rate.

He said the key reason to provide the bombs is to keep Ukraine in the fight.

“Things are going a little slower than some had hoped,” Kahl said in a Pentagon briefing. “So this is to make sure that the Ukrainians have the confidence that they have what they need. But frankly, also that the Russians know that the Ukrainians are going to stay in the game.”

Kahl said the Ukrainians have provided written assurances that they will not use the munitions in urban areas that are populated by civilians and that there will be a careful accounting of where they are employed.

Questioned at length about the decision, Sullivan said the US consulted closely with allies before making the final decision, noting that even allies who have signed on to a ban of the bombs “have indicated, both privately and many of them publicly over the course of today, that they understand our decision.”

Allies “recognize the difference between Russia using its cluster munitions to attack Ukraine and Ukraine using cluster munitions to defend itself, its citizens and its sovereign territory,” he said. The US “will not leave Ukraine defenseless at any point in this conflict, period.”