The probe, which found Israel’s military had misjudged Hamas’ intentions, is likely to put further pressure on Prime Minister Benjamin Netanyahu.
Israel’s refusal to leave the Philadelphi Corridor threatens to collapse a fragile ceasefire deal with Hamas.
Prosecutors say the suspects established arms depots in Bulgaria and Denmark, and were plotting attacks in Germany and beyond.
Israeli Prime Minister Benjamin Netanyahu delays the release of hundreds of Palestinian prisoners abruptly putting the future of the truce into further doubt.
The six included three Israeli men seized from the Nova music şenlik and another taken while visiting family in southern Israel when Hamas-led militants stormed across the border in the 7 October, 2023, attack that triggered Israel’s 16-month bombing campaign in Gaza.
The Bibas family include a mother and two children whose whereabouts were widely speculated on.
After Hamas said it will release six living Israeli hostages and return four bodies, family members expressed both happiness and grief ahead of the release, while Palestinians in Gaza maintain hope that the ceasefire will hold.
Hamas is set to release six living Israeli hostages on Saturday and four bodies before then.
The Palestinian group recently said they could delay the release of hostages, after accusing Israel of breaching some of the terms of the ceasefire agreement.
A fragile ceasefire between Israel and Hamas in the Gaza Strip took hold in January.