A US-based aid group admitted Friday that a group of individuals — who the Israeli military says were armed — took control of an aid convoy in the southern Gaza Strip the day before, without the organization having vetted them or coordinated the matter with the Israel Defense Forces.

The military said Thursday that it struck the gunmen, killing them while not harming aid workers.

According to the IDF, Hamas operatives frequently try to hijack aid deliveries.

The IDF had said on Thursday that a convoy of aid trucks from the American Near East Refugee Aid (Anera) organization entered the southern Rafah area with Israeli coordination. It said that during the drive, it identified a group of gunmen taking over a vehicle at the front of the convoy and beginning to lead it. The IDF described the act as a hijacking attempt.

Shortly afterward, the IDF said it was able to determine that it could strike just the car with the gunmen, without harming the rest of the convoy, and so it carried out a strike, killing at least four.