The uprising began at the Józef Stalin Metal Works, now the Hipolit Cegielski factory, amid anger over wages, production quotas and working conditions. The protest began as an industrial dispute but expanded into a wider demonstration against the Stalinist authorities. Workers marching toward central Poznań were joined by residents, students and employees of other plants, swelling the crowd to about 100,000 people. In response, the communist authorities deployed more than 10,000 troops and around 400 tanks against the protesters. At least 58 people were killed and hundreds wounded before the unrest was suppressed. President Karol Nawrocki is due to attend the main anniversary ceremony at Adam Mickiewicz University Auditorium with the presidents of Albania, Latvia and Hungary. The main ceremony begins at 5:30 p.m. local time.