#OnThisDay, 9th of August 1971, internment was re-introduced in the North with a large wave of arrests and imprisonments in dawn raids. Aimed at weakening the IRA, 342 people were arrested in the initial action, all from Nationalist or Republican backgrounds. Several days of violence and protest followed immediately afterwards.
https://www.leftarchive.ie/calendar/on-this-day/08/09/#event-5734