WASHINGTON, Sept 26: Ugandan authorities have arrested 20 people, including two ring leaders and followers of Osama bin Laden, who had allegedly planned to bomb the US embassy in Uganda, US media reports said today.On a tip-off from CIA, more than a dozen FBI agents worked with the Ugandan anti-terrorist squad to unravel the plot, the Washington Post quoted officials as saying. One of those arrested was a 15 year-old boy. Reacting to the arrests, Amnesty International said in a statement that Uganda should charge the arrested suspects with specific crimes or let them go.Although Ugandan law requires suspects to be charged within 48 hours of their arrest, last year a number of Muslims were detained there without trial.