TIRANA (RUTER) - Some 3,000 Albanians forced their way past police with batons and water cannon on Sunday to hold a protest in Tirana`s main Skanderbeg Square, defying government warnings against the demonstration, eyewitnesses said. The crowd, led by opposition party leaders, burst through police cordons to reach the square, symbolic as the scene of a 1990 uprising that toppled Albania`s communist regime, shouting: "The police are with us, the government is a thief". The protest was called after a week of minor demonstrations against collapsing pyramid investment schemes in which hundreds of people have lost their life savings. President Sali Berisha vowed on Saturday to crack down on pyramid investment schemes but warned the opposition against exploiting anger among investors to try to destabilise the ex-communist state. Three dubious investment groups have collapsed in the past few weeks in Albania, Europe`s poorest country. Infuriated investors clashed with baton-wielding police on Wednesday in a demonstration over the investment projects.