US President Barack Obama and wife Michelle arrived in Pittsburgh before greeting world leaders for the beginning of the G20 summit.A relaxed atmosphere before getting down to the nitty gritty on how best to reshape the global economy. One key proposal being pushed by Washington, London and Paris is to shift the emphasise away from the G8 and give more power to the world’s emerging economies. But, the EU remains unsure about the idea and what role it would play in any new make up. Italy’s Prime Minister Silvio Berlusconi is also worried that any expansion of the G8 to include countries like China and India would drain away Italian influence at the world table. President Nicolas Sarkozy and wife Carla brought a touch of French glamour to proceedings. Paris is pushing for tougher banking regulation and the G20 has broadly agreed on new rules for financial institutions and how to cap excessive bankers bonuses. Protests against capitalism are surrounding the event. Clashes broke out between riot squads and hundreds of protesters on the outskirts of Pittsburg as the marchers attempted to make their way to the convention centre where the summit was being held. Authorities who had declared the rally unlawful, played announcements and used tear gas to push the crowd back. Police said only a handful of around 2000 protesters were arrested. Bigger demonstrations were expected later today in various parts of Pittsburg.