At least 38 human rights organizations have publicly declared their opposition to the delivery of cluster bombs to Ukraine, underlining concern over the weapon's ability to drop bomblets that could endanger civilians for years by failing to detonate and remaining as explosive hazards, The Hill newspaper reported.

White House National Security Advisor Jake Sullivan confirmed on Friday that although the decision was "difficult to make", US leader Joe Biden ultimately decided to provide Ukraine with cluster munitions for its counteroffensive after consulting with allies and lawmakers.

During a press briefing, Sullivan said: "It's a difficult decision...There was a unanimous recommendation from the national security team, and President Biden ultimately decided, in consultation with allies and partners and in consultation with members of Congress, to move forward on this step".

Just hours before, humanitarian organizations condemned the initial plans to supply the cluster munitions after citing the long-lasting threat posed by them since they leave behind unexploded bomblets.

The arms delivery comes as the Ukrainian troops are using "high rates" of ammunition and amid concerns on Washington's end that Ukraine's counteroffensive against Russia-held territories has stalled, the report said on Friday.

Prominent international rights groups urged for an end to the use of cluster munitions in the Ukraine war and said that the country should be cleaned up of such bombs.

"These are already all over the country and will need to be cleaned up. That is not a good enough excuse for the United States to be sending more. Legislators, policymakers, and the Biden administration will probably think twice when the pictures start coming back of children who have been harmed by American-made cluster munitions," Sarah Yager, the Washington director at Human Rights Watch, was quoted as saying by the US newspaper.

Baptiste Chapuis of Handicap International - Humanity and Inclusion (HI) said: "This is a death sentence to civilians over the long term. There are people who have not yet been born who will fall victim" to cluster bombs.

"The USA's plan to transfer cluster munitions to Ukraine is a retrograde step, which undermines the considerable advances made by the international community in its attempts to protect civilians from such dangers," Amnesty International researcher Patrick Wilcken said in a statement. HRW "urges the USA to reconsider".

Russia already warned the US against sending the cluster munitions to Ukraine, and Russian Ambassador to the UN Vassily Nebenzia argued it would count as a bigger step toward escalating the conflict.

Washington is crossing the line by supplying Ukraine with cluster munitions, Federation Council Committee on Foreign Affairs First Deputy Chair Vladimir Dzhabaro told Russian news agency Sputnik.

"What will happen next?" he wondered. "Atomic Weapons? First, there was depleted uranium, then the real deal. That is, they are already going to the end," Dzhabarov said, underlining that Moscow would seek the destruction of supply channels.

The United States was reported in June to have been on the verge of approving a package of ammunition that includes depleted uranium rounds.

The package, which is under debate at the White House, aims to provide support for the Ukrainian counter-offensive as they continue their efforts to regain territory from Russian forces.

While political support for Ukraine remains strong on Capitol Hill, some lawmakers caution that backing may diminish if Ukraine's counteroffensive falls short. They argue that the White House should be more supportive of Ukraine's current arms requests.