Amnesty International on Friday criticized the police's response to protests in Ferguson, Missouri, which were triggered by the shooting death of Michael Brown on Aug. 9, and called for the officers involved to be investigated by U.S. authorities. The international human rights organization had sent a delegation to the St. Louis suburb to oversee law enforcement practices during protests in August.

The group, which monitored police behavior between Aug. 14 and Aug. 22, reportedly said that the use of rubber bullets, tear gas and heavy-duty military-grade equipment violated international standards and risked the lives of demonstrators. It also reportedly said, in a 23-page report, that “at least two children were treated for exposure to teargas” during the protests. The report stated that most of the excessive force was undertaken to quell peaceful protests.

“The police should not intervene aggressively simply in response to the actions of a small number of participants,” the report stated, according to The Guardian. “Assemblies are always diverse gatherings, and participants do not lose their individual rights simply because a small number of people are behaving violently.”

Margaret Huang, deputy executive director for campaigns and programs for Amnesty International, reportedly said that the methods used by police to control the protests, which sometimes grew violent, violated citizens' basic rights.

“There were a number of substantial concerns about the violation of the right to peacefully protest,” Huang said, according to St. Louis Public Radio. “There were more than 170 people arrested in the first 12 days of the protest after Michael Brown’s shooting and more than three-quarters of those were for the refusal to disperse.”

The Amnesty report also reportedly criticized the midnight curfew that was imposed after several days of unrest in the region, and raised concerns over the arrests of journalists covering the protests.

Rachel Ward, director of research at Amnesty International, said that the report urges state lawmakers to make the use of lethal weapon by police a last resort under Missouri law, Reuters reported.

Meanwhile, the state's police force has reportedly been preparing for a grand jury’s decision about whether Darren Wilson, the white police officer who shot Brown, should be criminally charged. The Associated Press reported that police had been stocking riot gear to prepare for the possibility of an outbreak of violence after an announcement of the grand jury's decision, which is expected by November.