London police said Sunday that 532 people were arrested the previous day when supporters of a pro-Palestinian group that was recently outlawed as a terrorist organization intentionally broke the law.

Thousands marched through the streets of central London Saturday to protest against the ongoing war in Gaza. The protest, organised by the Palestine Solidarity Campaign, called for an end to Israel’s offensive in Gaza.

Police in London have detained more than 466 people who were protesting the United Kingdom’s decision to ban the Palestine Action Group, marking the “largest ever mass arrest” at a single protest in the British capital, according to campaigners.