The possibility of a coup was not taken very seriously in Latvia at the time, so the morning of August 19, when the military machinery of the Soviet army blocked the main routes of access to Riga, came unexpectedly. By the evening, the Latvian Television building and the Internal Affairs Ministry had been taken over.
31 year ago attempt of coup d’état began in #Moscow, as a result Soviet Union disappeared. We all hoped for the new and better chapter of history. Unfortunately, #Russia is again totalitarian and aggressive power. Also this evil empire will collapse, better sooner than later— Edgars Rinkēvičs (@edgarsrinkevics) August 19, 2022
On August 21, with Special Purpose Mobile Unit OMON armored vehicles in Doma Square, the Supreme Council adopted a constitutional law on the status of Latvia as an independent state. Two days later, a red-and-white flag flew over the building of the Central Committee of the Communist Party of Latvia. The putschists had lost.
If you wish to take a look at additional materials on the August coup in Latvia, you can watch a short documentary here or last year's informative video by the Saeima here, complete with English subtitles. A full documentary was produced by LTV last year, available here.