US President Barack Obama has phoned Ghana's new president and congratulated him on the African nation's peaceful transfer of power. The White House says Obama phoned President John Atta Mills on Friday to discuss fighting the narcotics trade that threatens West Africa. Obama also praised Ghana for its democratic process, especially considering recent coups in Mauritania, Guinea and Madagascar. Atta Mills took office after a peaceful but tense ballot that was the closest vote in the country's history. It was the second time power has been successfully transferred from one legitimately elected leader to another in Ghana. Atta Mills took office on Jan. 7.