Police said Wednesday they had arrested 47 people as tensions rose after an otherwise peaceful night of protests in Ferguson, the Missouri town rocked by violence over the police shooting of an unarmed black teenager. Three guns were seized in the latest protest rally in Ferguson, which has become ground zero of a new national debate on police treatment of minorities after Michael Brown, 18, was shot August 9 by a white police officer. Captain Ron Johnson of the Missouri Highway Patrol said protesters threw glass and plastic bottles of water and urine at police towards the end of Tuesday night's protest, prompting officers to intervene and make the arrests.Johnson stressed that unlike a violent protest Monday night, this time protesters did not fire guns at police and officers refrained from using tear gas to break up the rally.