US Defense Secretary Lloyd Austin received a letter from two Congress members asking for a formal probe into the potential undercounting of civilian deaths caused by US airstrikes and military clashes.

The letter stated that the estimated losses may be as much as five times higher than official Pentagon numbers, basing their numbers on independent sources.

Senators Elizabeth Warren and Ro Khanna discussed the Department of Defense's (DoD) report last month, which acknowledged 23 civilian deaths and ten injuries caused by its operations in Afghanistan, Iraq, and Somalia during 2020. 

The two senators also said: "We need to openly consider all the costs, benefits, and consequences of military action, and that includes doing everything we can to prevent and respond to civilian harm."

The letter also states that the Pentagon has not used "any of its $3 million allocations for condolence... payments," which would have been "more than enough for payments to every victim's family."

113 international human rights organizations had previously asked President Biden to end lethal strikes outside recognized battlefields, or the use of UAVs, because they are illegal and "have caused significant civilian casualties."