BRASILIA - Public transportation workers in Brazil's Sao Paulo went on strike Thursday, causing a massive traffic jam in the country's largest city.

Four of the city's six subway lines were totally paralyzed due to the strike.

The city government was forced to suspend the usual rotating day-without-a-car program, which worsened the traffic as cars flooded the streets.

By noon, vehicles were backed up for 148 kilometers, amounting to 17 percent of the city's monitored roadways.

Worker union leaders said the strike was a response to the government's failure to consider their demands for a salary increase.

The strike came just two days after a large-scale demonstration by Sao Paulo students against higher bus fares.