The United States-backed Gaza Humanitarian Foundation has accused militant group Hamas of attacking a bus carrying its staffers to an aid distribution centre, saying at least five people were killed and multiple others injured.

The group said in a statement that around 10 pm local time “a bus carrying more than two dozen members of the Gaza Humanitarian Foundation team ... were brutally attacked by Hamas”.

“We are still gathering facts, but what we know is devastating: there are at least five fatalities, multiple injuries, and fear that some of our team members may have been taken hostage,” the statement read.

In an email to AFP the group said all the passengers on the bus were Palestinian and all were aid workers. They were en route to GHF’s distribution centre in the area west of Khan Younis.

“We condemn this heinous and deliberate attack in the strongest possible terms,” the group said in its statement.

“These were aid workers. Humanitarians. Fathers, brothers, sons and friends, who were risking their lives every day to help others.”

An officially private effort with opaque funding and backed by Israel, GHF began operations on May 26 after Israel completely cut off supplies into Gaza for more than two months, sparking warnings of mass famine.

But GHF’s first week of operations, in which it said it had distributed more than seven million meals’ worth of food, has been marred by criticism.

The Israeli military faces allegations of shooting into crowds of civilians rushing to pick up aid packages near GHF sites.

Israeli authorities and the GHF - which uses contracted US security - denied any such incident took place.

The United Nations and major aid groups have refused to co-operate with the foundation over concerns it was designed to cater to Israeli military objectives.

-Agence France-Presse