Amnesty International has said the US must look at its own human rights abuses before commenting on other countries, in the wake of the protests in Ferguson.
The human rights campaigners have criticised the use of force and military equipment by the police in their attempt to control the disorder in the Missouri town following the shooting of unarmed black teenager Michael Brown by officer Darren Wilson.
There have been 10 days of unrest in Ferguson, including the use of tear gas and rubber bullets against protesters and the arrest of journalists and photographers attempting to cover the events.
The clashes between police and protesters led to Missouri governor Jay Nixon pulling Ferguson Police "out of the situation" and replacing them with the National Guard.
As the protests continue, Amnesty International tweeted saying the US should "clean up its own human rights record" before telling other countries to do the same.
The tweet was sent after the group called for a full investigation into police tactics used during the protests.
"Amnesty International has a long and tested history of monitoring and investigating police conduct, not just in foreign countries, but right here at home in the United States," said Steven W. Hawkins, executive director of Amnesty International USA.
"Our delegation travelled to Missouri to let the authorities in Ferguson know that the world is watching. We want a thorough investigation into Michael Brown's death and the series of events that followed."
The tweet from Amnesty echoed a similar sentiment by Iran's Supreme Leader Ayatollah Ali Khamenei, who described the US government as "the biggest violator" of human rights.
Human Rights Watch recently published a report condemning Iran for holding several dozen prisoners in jail for "exercising their basic rights" such as exercising free speech and rights to peaceful assembly or association.
Discussing Ferguson, Hawkins added: "We must seize this moment to bring about a wide-ranging review of all trainings, policies and procedures with regard to the use of force and the policing of protests in Ferguson and around the country.
"This is a moment for people around the country – and around the world - to join the Ferguson community in raising concerns about race and policing, and about the impact of militarisation on our fundamental right to peacefully assemble."
An autopsy ruled Brown was shot six times by officer Wilson, including twice in the head.