The Biden administration announced on Friday that they will be providing thousands of cluster munitions to Ukraine, citing the need to bolster Ukraine's offensive against Russian forces.

The controversial decision has raised questions and concerns from NATO allies, as over 120 countries have signed on to a convention banning the use of cluster bombs due to their track record for causing civilian casualties.

The munitions the US will be sending to Ukraine have been designed to have a reduced dud rate, meaning fewer of the smaller bomblets fail to explode and remain on the battlefield after use.

The US will also be sending an €735 million package of military aid to Ukraine, which includes Bradley and Stryker armoured vehicles as well as ammunition. The US has been taking massive amounts of 155 mm rounds from Pentagon stocks and sending them to Ukraine, creating concerns about eating into American stores.

The cluster munitions, which are fired by the same artillery as the conventional 155 mm, will allow Ukraine to strike more Russian targets using fewer rounds. The Pentagon has "multiple variants" of the munitions and they will be carefully selecting rounds with lower dud rates, for which they have recent testing data.

Reactions from allies have been muted, with NATO Secretary-General Jens Stoltenberg stressing that the military alliance takes no position on cluster munitions and it is a decision that allies will make. The US has previously used cluster munitions during the 2003 invasion of Iraq and the 2001 invasion of Afghanistan.

Proponents of banning cluster bombs say they kill indiscriminately and endanger civilians long after their use. The UN human rights office has urged Russia and Ukraine to join the over 100 countries that have ratified the convention of cluster munitions and that effectively ban their use.