The United States has planned to send globally banned cluster munitions to Ukraine to help it battle Russian forces, American officials have said.

Speaking on condition of anonymity, three US officials said on Thursday that the weapons aid package would include cluster munitions fired by a 155-millimeter Howitzer cannon. The package is expected to be announced as soon as Friday.

Cluster bombs are banned under the Convention on Cluster Munitions (CCM), an international treaty that addresses the humanitarian consequences and unacceptable harm caused to civilians by cluster munitions through a categorical prohibition and a framework for action.

The weapons can contain dozens of smaller bomblets, dispersing over vast areas, often killing and maiming civilians. The CCMs are banned because unexploded bomblets can pose a risk to civilians for years after the fighting is over.

Cluster munitions generally eject submunitions that can cover five times as much area as conventional bombs.

The Convention on Cluster Munitions, which took effect in 2010, bans all use, production, transfer and stockpiling of cluster bombs. More than 100 countries have signed the treaty, but the US, Russia and Ukraine have not.

One of the officials told the Reuters news agency that the measure has been under serious consideration for at least a week.

The White House said sending cluster munitions to Ukraine is “under active consideration.”

The Ukrainian government has called on members of Congress to press President Joe Biden’s administration to approve sending Dual-Purpose Conventional Improved Munitions (DPICM).

A Pentagon spokesman said the Biden administration was considering sending DPICMs to Ukraine, but only those that had a failure rate lower than 2.35%.

The US military believes cluster munitions would be useful for Ukraine, a senior Pentagon official said in June.

Laura Cooper, who is the deputy assistant secretary of defense for Russia, Ukraine and Eurasia at the US Defense Department, made the remarks on June 22 while addressing US lawmakers.

“Our military analysts have confirmed that DPICMs would be useful, especially against dug-in Russian positions on the battlefield,” she told lawmakers during a Congressional hearing.

“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,” Cooper added.

US to decide whether to send banned cluster munitions to Ukraine: Media

The US may decide this week whether to send controversial cluster munitions to Ukraine, a media report says.

So far, the Biden administration has refrained from officially sending any cluster munitions to Ukraine.

However, even though the export of such weapons has been banned by Congress, media outlets such as Politico have suggested that Biden and even his Secretary of State Antony Blinken could potentially override this ban.

An American adviser to the Ukrainian military has also called on Washington to send Kiev forces cluster munitions to fight Russia.

Dan Rice said in December last year that the US “really needs to” supply Kiev’s forces with cluster bombs to increase “base lethality” and “win the war” against Russia.