Tunisia\'s Prime Minister Beji Caid Essebsi said Tuesday that police were banned from engaging in union activities which he said were a threat to the country\'s security. \"I have decided from today to ban all union activity among security services in view of the danger that such activity represents for security of the country,\" he said at a press conference. Tunisian police, angered at charges of killing protesters, were planning a sit-in on Tuesday outside the main government building in Tunis, security forces unions said.