Dozens of villagers blocked roads Tuesday around US Steel Serbia near the town of Smederevo to protest alleged pollution by the steelmaker. "We give the authorities 90 days to do something and protect the environment," local official Mr Milan Kostic said. "We have to protect the lives of our children."

The villagers say pollution in the area has increased considerably since last summer, but that the authorities have done nothing to determine the danger to people's health.

US Steel Serbia is owned by US Steel Corp, which bought Serbia's biggest but bankrupt steelmaker Sartid Co in 2001. The factory has revived production since 2001, becoming one of Serbia's most successful companies.

There was no immediate comment from U.S. Steel.