An exiled former minister of the Republic of Congo is plotting a coup along with two white foreigners, other mercenaries and accomplices in the army, state radio quoted the interior minister, Gen. Paul Mbot, as saying. Gen. Paul Mbot, the Interior minister, said authorities were searching for two whites who he said have been shuttling back and forth between Brazzaville and Kinshasa, the capitals of the two Congos that are separated by the Congo River. Mbot said the coup was in a "preparatory phase," and was being masterminded by Nguila Moungounga Nkombo, a former finance minister in the government of Pascal Lissouba, who lost power in 1997 during a civil war. Both men live in Paris.