The Axis powers invaded Yugoslavia on 6 April 1941. Vladko Maček, the leader of the Croatian Peasant Party (HSS), which was the most influential party in Croatia at the time, rejected German offers to lead the new government. On 10 April the most senior home-based Ustaše, Slavko Kvaternik, took control of the police in Zagreb and in a radio broadcast that day proclaimed the formation of the Independent State of Croatia ("Nezavisna Država Hrvatska", NDH). The name of the state was an attempt to capitalise on the Croat struggle for independence. Maček issued a statement that day, calling on all Croatians to cooperate with the new authorities.