The United States announced on Friday that it will provide cluster munitions to Ukraine for the first time as Kyiv's forces push ahead with a counter-offensive against Russian forces.

The move has drawn sharp criticism from rights groups due to the danger unexploded bomblets pose even after a conflict has ended, but Washington said it had received assurances from Kyiv that it would seek to minimise the risk to civilians.

A new military aid package "will provide Ukraine with additional artillery systems and ammunition, including highly effective and reliable dual-purpose improved conventional munitions (DPICM)," the Pentagon said in a statement, referring to cluster munitions.

US National Security Adviser Jake Sullivan said President Joe Biden had approved the decision, describing it as the "right thing to do," and said the need to help Ukraine counter Russian forces outweighs the risk.

There is "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," Sullivan told journalists.

Kyiv "has provided written assurances that it is going to use these in a very careful way that is aimed at minimising any risk to civilians," he said, noting that Ukraine's government "has every incentive to minimise risk to civilians, because it's their citizens."

Pentagon spokesman Brigadier General Pat Ryder told journalists ahead of the announcement that DPICMs are "clearly a capability that would be useful in any type of offensive operations."

"It can be either loaded with shaped charges which are armour penetrating or they can be loaded with fragmentary munitions which are anti-personnel," Ryder said.

But rights groups have come out strongly against the United States providing the munitions.

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

Amnesty International said Biden's administration "must understand that any decision enabling the broader use of cluster bombs in this war will likely lead to one predictable outcome: the further death of civilians."

"Cluster munitions are an indiscriminate weapon that presents a grave threat to civilian lives, even long after a conflict has ended. Their transfer and use by any country under any circumstances is incompatible with international law," it added. (AFP)