KABUL, Afghanistan –  International medical charity Doctors Without Borders says the death toll from a U.S. airstrike on its hospital in northern Afghanistan has risen by one, after it confirmed the death of a staff member.

The group, which is also known by its French acronym MSF, says in a statement Friday that the death toll from the Oct. 3 attack on the compound in Kunduz city now stands at 23, with 13 staff members killed and 10 patients killed. Many were wounded.

MSF says it’s trying to determine the identities of seven bodies found in the wreckage which were unrecognizable and have since been buried.

U.S. President Barack Obama apologized for the bombing and the commander of U.S. and NATO forces in Afghanistan has said it was a mistake. Investigations are underway.