KATHMANDU: As many as 12 cadres of Janata Samajbadi Party (JSP) have been arrested for waving black flags at CPN UML Chair KP Sharma Oli. JSP cadres had waved black flags to the UML chair in Janakpur on Saturday. Oli reached Janakpur today to welcome some leaders of the Loktantrik Samajbadi Party (LSP) into the UML.