Hamas killed eight Gaza Humanitarian Foundation workers and injured several others in what the group says was an "unprovoked" attack. GHF fears some of those who were attacked may have been taken hostage.

The team was en route to a distribution center, working alongside local Palestinians to deliver aid to the Gazan population.

The group, which has been harshly criticized by the U.N. and other aid providers, said at least five people had died in an attack on one of its buses.