Tens of thousands of workers marched Wednesday to governments offices across the country during a day of strikes that brought South Africa's largest cities to a standstill. The escalation of a 12-day-old strike staged by public sector unions disrupted schooling, health care and transport services. Municipal workers also heeded the call to put down their tools in a show of solidarity that also saw a number of other unions take parts in lunchtime protests. With a heavy police presence in all cities, the protests went off peacefully and there were no reports of violence as workers rallied for higher wages. "We are not moving back not one inch," the Congress of South African Trade Unions general secretary Zwelinzima Vavi told several thousand people at a rally outside the gates of parliament in Cape Town, the South African Press Association reported. "So the government has a choice: Do they see a long winter or do they want to settle?" About 1 million teachers, nurses and other civil servants have been on a strike since June 1, leaving hospitals struggling and prompting the government to call in soldiers and police to protect non-striking workers and other civilians. The public sector unions rejected the government's latest offer Tuesday to boost salaries by 7.25 percent, up from an original offer of 6 percent. The unions are demanding a 10 percent increase, down from 12 percent initially. Medical workers have joined the public sector strike, even though as "essential workers," they are legally barred from going on strike. The government has said striking medical workers would be fired, and dismissals have been announced at some hospitals. Unions condemned the firings, and patients have expressed support for the strikers at some hospitals. But there also have been reports of strikers intimidating those who have continued to work. About 30 strikers were arrested Monday, accused of intimidating staff at a hospital in the central city of Bloemfontein. And on the first day of the strike, police fired stun grenades to disperse around 500 protesters who were preventing doctors from entering one of Cape Town's largest hospitals. Police and prison staff unions also have threatened to join the strike in a show of solidarity. Fewer commuter trains were reported to be running Wednesday, while security was increased at some hospitals. Many schools were shut for the day. The ruling African National Congress called striking workers to ensure there was calm and "resist those elements that are bent on acts of violence and intimidation." On Tuesday, President Thabo Mbeki voiced support for a revised salary structure for public sector workers while condemning the intimidation and violence. "All of us should ask ourselves what kind of society we are building and what moral lessons we are imparting when insults, violence against fellow workers and damage to property become the stock-in-trade during protests of this kind," he said.