Protestors and police clashed at demonstrations in front of the Greek parliament building in Athens on Tuesday, where police estimated at least 40,000 people showed up to decry German Chancellor Angela Merkel\'s visit with Greek Premier Antonis Samaras. Demonstrators threw stones at a police barricade that prevented them from nearing the parliament building where the meeting was taking place. Police in riot gear shot back with tear gas. Smoke bombs and Molotov cocktails were lobbed by masked demonstrators against police on a side street near the demonstration. Police dispersed the disguised youths by charging them. Demonstrators burned a Nazi flag with a swastika in front of the Greek parliament building. Police arrested three for possession of illegal weapons and stopped 36 during the morning for violating a temporary ban on public gathering, declared Monday in anticipation of Merkel\'s visit. Greek unions ADEDY and GSEE organized the demonstration to condemn Merkel\'s presence and new austerity measures called for by the troika - the European Union, the International Monetary Fund and the European Central Bank - to restructure Greece\'s huge public debt.