Police in Likoni, Mombasa County, arrested more than 40 people suspected of belonging to the Mombasa Republican Council after a late-evening operation at Shelly Beach.
Likoni Deputy County Commissioner Eric Wamlevu said the group was found taking an illegal oath and had not obtained a permit for the gathering.
Officers later displayed dozens of MRC membership cards they said were recovered from the suspects at Likoni Police Station.
Police said those arrested came from Kwale, Lamu and Kilifi counties. They also said identity cards showed the suspects were between 35 and 70 years old.
