New York attorney general sues NYPD over 'brutal' protest crackdown
Anti-racism protesters and police face off in Brooklyn, New York, in June 2020 (AFP)

New York state's attorney general sued the NYPD on Thursday, accusing America's largest police force of using "brutal" force during last year's massive Black Lives Matter protests.

Letitia James said New York City police officers falsely arrested peaceful demonstrators, unlawfully detained legal observers and deployed "indiscriminate, unjustified" repeated use of batons and pepper spray.

James, a Democrat, added that the actions "led to significant injuries and violated individuals' basic right to peacefully protest."

Tens of thousands of people marched in New York in May and June as part of protests that swept America for days following the killing of George Floyd in police custody in Minneapolis.

The NYPD was criticized for its heavy handed response, with numerous videos circulating online showing officers charging at peaceful demonstrators and deploying a controversial crowd-control tactic known as "kettling."

"There is no question that the NYPD engaged in a pattern of excessive, brutal, and unlawful force against peaceful protesters," James said in a statement.

In her complaint, the civilian prosecutor calls for an external monitor to be set up to oversee the NYPD's policing tactics at future protests.

The lawsuit filed in Manhattan also specifically charges Commissioner Dermot Shea, Chief of Department Terence Monahan and Mayor Bill de Blasio, who as head of the city government is effectively their boss.

De Blasio largely defended the police response, while promising a review of alleged abuses and the imposition of penalties if necessary.

Looting on the sidelines of the protests led to de Blasio imposing a week-long nighttime curfew on the city.