CAIRO (AP) — A unit of Gaza’s Hamas-run police force said it killed 12 members of an Israeli-backed Palestinian militia after detaining them early Thursday. An Israel-supported aid group, however, said the dead were its aid workers, eight of whom were killed when Hamas attacked their bus.

It was not immediately possible to verify the competing claims or confirm the identities of those killed. The militia, led by Yasser Abu Shabab, said its fighters had attacked Hamas and killed five militants but made no mention of its own casualties. It also accused Hamas of detaining and killing aid workers.

The deaths were the latest sign of turmoil surrounding the Gaza Humanitarian Foundation, a private contractor that Israel says will replace the U.N. in distributing food to Gaza’s more than 2 million people. The past two weeks, dozens of Palestinians have been killed and hundreds wounded in near daily shootings as they try to reach GHF centers, with witnesses saying Israeli troops nearby have repeatedly opened fire.