Police in a drive arrested 21 leaders and activists of Jamaat-e-Islami and Chhatra Shibir from Chamagram village of Chapainawabganj Sadar upazila early Tuesday.At this time, 500 grams gun powder and 30 cocktails have been recovered from their possession.Officer-in-charge of Chapainawabganj Sadar police station, Mazharul Islam said, acting on a tip-off we heard that Jamaat-Shibir men were arranging a secret meeting. Later we conducted a drive at that area. Sensing the presence of us, some of the leaders and activists managed to flee away and 21 others were held, he added.