In their strongest use of force yet against the independent union Solidarity, Polish authorities sent Army troops and riot police Wednesday to storm a paramilitary academy where 300 Solidarity-backed strikers were staging a sit-in.
The action, though free of violence, prompted Solidarity chairman Lech Walesa to call a nationwide emergency alert of the union. Solidarity leaders met in emergency session, while workers at Warsaw's huge steel mill and tractor plant said they were ready to go on strike at once.
Helmeted riot police stormed the roof of the building with a helicopter. Other police fired tear gas into the windows. The firefighting cadets, who showed no resistance, were led into buses and released outside town.
The government move followed a vow by Prime Minister Wojciech Jaruzelski to get tough with the union, including the possibility of passing legislation banning all strikes. The cadets were striking to try to force the government to remove their institution from the military school system.