(ASNA) - Rome, September 10 - A group of workers and labor union representatives from the Alcoa aluminum plant on the island of Sardinia will arrive in the Italian capital Monday for a 'march on Rome' following a weekend of increased tension over a bomb scare at the plant on Saturday. A squad of bomb experts safely exploded a device on Saturday left outside of Alcoa Inc. that was equipped with a remote activation device. Police are investigating the explosive's origins. Labor unions and the government have been locked in a dispute with the American aluminum giant over the company's move to shut down a smelter and put hundreds of jobs at risk. Alcoa has promised to keep all workers at its Portovesme plant in Sardinia employed through the end of the year.