How Hamas built a force to attack Israel on 7 October

Five armed Palestinian groups joined Hamas in the deadly 7 October attack on Israel after training together in military-style exercises from 2020 onwards, BBC News analysis shows.

The groups carried out joint drills in Gaza which closely resembled the tactics used during the deadly assault - including at a site less than 1km (0.6 miles) from the barrier with Israel - and posted them on social media.

They practised hostage-taking, raiding compounds and breaching Israel's defences during these exercises, the last of which was held just 25 days before the attack. read more