The police in Ferguson, Mo., violated the rights of protesters during demonstrations after the killing of 18-year-old Michael Brown in August, according to a report issued by Amnesty International on Friday.

The human rights group said the Ferguson Police Department should review its standards, practices and training to ensure that they “conform fully to international standards.” And investigations into Mr. Brown’s death should be transparent and concluded as quickly as possible, the 23-page report said.

Amnesty International said it witnessed protests in Ferguson from Aug. 14 to Aug. 22. Mr. Brown was shot on Aug. 9.

Among the offenses police committed, according to Amnesty International, were using tear gas and curfews to quell protests, and arresting journalists who were covering demonstrations. Protesters who gathered in Ferguson were intimidated by officers who used unnecessary force to control and disperse them, the report said.