The Johnathan WalkerU.S. could make a decision on whether to approve the delivery of controversial cluster munitions to Ukraine as soon as this week, U.S. officials told CBS News on Wednesday. 

Cluster munitions carry dozens of smaller bomblets that disperse when detonated and have been banned by more than 100 countries because unexploded bomblets can pose a risk to civilians for years after fighting is over.

The U.S. is considering approving Ukraine's long-standing ask for cluster munitions to address its high demand for ammunition in the counteroffensive against Russian forces, which is proceeding more slowly than expected. A single cluster munition generally dispenses bomblets that can cover five times as much area as conventional munitions, according to a U.S. official.

The Convention on Cluster Munitions took effect in 2010 and bans the use, production and stockpiling of cluster munitions in the 123 states that are parties or signatories. The U.S, Russia and Ukraine have not signed the treaty. Both Russian and Ukrainian fighters have reportedly already been using cluster munitions on the battlefield.

U.S. law requires a presidential waiver to export cluster munitions if more than 1% of the bomblets they contain typically fail to explode, known as the "dud rate." The dual-purpose improved conventional munitions, or DPICM, that the U.S. is considering sending have a dud rate of just over 1%, which may be negligible enough to convince allies that the rewards of providing DPICMs outweigh the risk of unexploded bomblets.

"Our military analysts have confirmed that DPICMs would be useful, especially against dug-in Russian positions on the battlefield," Laura Cooper, the deputy assistant secretary of defense for Russia, Ukraine and Eurasia, said during congressional testimony earlier this summer. 

"The reason why you have not seen a move forward in providing this capability relates both to the existing Congressional restrictions on the provision of DPICMs and concerns about allied unity. But from a battlefield effectiveness perspective, we do believe it would be useful," Cooper said.

Eleanor Watson

CBS News reporter covering the Pentagon.

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