A medical charity whose hospital in northern Afghanistan was bombed by the U.S. military said on Thursday that a U.S. tank forced its way through the closed gates of the compound, contravening an agreement that they would be informed, according to AP. Doctors Without Borders, also known as MSF, said they were informed after the "intrusion" that it was by a delegation from a joint U.S.-NATO-Afghan team investigating the Oct. 3 bombing of the hospital. The incident violated an agreement with investigators that MSF "would be given notice before each step of the procedure involving the organization's personnel and assets." "Their unannounced and forced entry damaged property, destroyed potential evidence and caused stress and fear," it said in a statement, adding that an MSF team had arrived at the hospital earlier in the day. Authorities in Kunduz and the U.S. military did immediately respond to requests for comment. The strike on the MSF trauma hospital in the northern city of Kunduz killed 10 patients and 12 staff. Another two staffers are now presumed dead, the group said this week, with all other MSF staff accounted for. U.S. President Barack Obama apologized for the bombing, which the commander of U.S. and NATO forces in Afghanistan, Gen. John F. Campbell called a "mistake."