Malawi's ruling United Democratic Front (UDF) expelled President Bingu wa Mutharika from the party on Sunday for misconduct, the country's home affairs minister said. Uladi Mussa, who walked out of a meeting of the UDF's national executive in protest, said party leaders had already decided to expel wa Mutharika and the executive had refused to discuss the matter. "They have made the decision to expel him already and calling for this meeting was just a formality," Mussa said. "The decision to expel him has already been made and what I was asking them in the meeting was to let us discuss the merits and demerits of doing that but they did not want to listen to me. This is why I decided to walk out," Mussa said. Sunday's developments highlighted a deepening power struggle between supporters of wa Mutharika and former president Bakili Muluzi, who remains UDF chairman, fuelled by a corruption crackdown in the impoverished southern African country. Critics of wa Mutharika, whose graft probe targeted the UDF's top ranks in the last eight months, say that he has shown disrespect to the party chairman and formed parallel structures to the ruling party. It was not clear what wa Mutharika's constitutional position would be if he was expelled from the UDF. --More 2138 Local Time 1838 GMT