The United States has decided to send cluster munitions to Ukraine to help its military push back Russian forces entrenched along the front lines.

The Biden administration is expected to announce on Friday that it will send thousands of them as part of a new military aid package worth $800 million, according to people familiar with the decision who were not authorized to discuss it publicly before the official announcement and spoke on condition of anonymity.

The move will likely trigger outrage from some allies and humanitarian groups that have long opposed the use of cluster bombs.