More than 10,000 people are marching past burned out and looted shops in central Athens, heading toward Parliament after four nights of rioting sparked by the fatal police shooting of a teenager. The demonstration is part of a previously scheduled nationwide general strike, but is developing into a protest at the government's handling of the crisis. Labor unions rejected an appeal by Prime Minister Costas Karamanlis to cancel Wednesday rallies, saying Greeks have a right to protest economic hardship. Emergency services are on alert across the city. The fears of renewed rioting during the rallies and the general strike are adding pressure on Greece's increasingly beleaguered conservative government.