New York, May 29 (IANS): At least 40 people were arrested in New York City as people took to the streets to protest against the death of a black man in police custody in Minneapolis.

Over 100 people gathered in Manhattan's Union Square on Thursday afternoon to express their anger over what they called police brutality that led to George Floyd's death, reports Xinhua news agency.

The 46-year-old African-American man died on Monday after a white police officer pinned him to the ground with a knee to the back of his neck while he was handcuffed and other officers stood by.

While being pinned down, Floyd repeatedly pleaded, "please, I can't breathe" and "don't kill me".

The four officers involved in the case were fired shortly after a video showing Floyd's death went viral on social media on Tuesday, sparking a national outcry for justice.

The incident has drawn comparisons to the 2014 death of New York African-American Eric Garner, who was put in a chokehold by police, despite his cries of "I can't breathe". His death galvanized the nationwide "Black Lives Matter" movement.

The New York City protesters chanted slogans, including "I can't breathe", while standing in lines face to face with dozens of policemen.

Some of them used abusive language toward police.

The 40 protesters were arrested after several scuffles and a fight between the two sides.

Local news reports said someone threw a trash can to police and another tried to grab an officers' gun, while NBC reported that a protester punched an officer in the face.

Demonstrations also took place as well in cities like Los Angeles and Memphis, according to media reports, while large-scale protests have turned violent in Minneapolis, for which Minnesota Governor Tim Walz on Thursday declared a state of emergency.

The incident concerning Floyd occurred on Monday night when after receiving a complaint, reportedly that a man might be trying to pass a counterfeit $20 bill at a local store, police officers arrived on the scene and found Floyd sitting in his vehicle, Efe news reported.

When they ordered him to get out, they said he resisted arrest, adding in their official report filed after the incident that after they had handcuffed him and made him lie facedown on the pavement they noticed that he was in "medical distress".

In the video taken by a passerby of Floyd's arrest and the events leading to his death, the man is seen lying facedown on the pavement beside a patrol car with one of the officers kneeling on the back of his neck for more than five minutes without changing position, despite the fact that Floyd can be heard saying that he cannot breathe and begging for the officers not to hurt him, until he ultimately loses consciousness.

"Please, please, please I can't breathe," and "My stomach hurts. My neck hurts. Please, please. I can't breathe," Floyd is heard saying. But the officer never reduced the pressure of his knee and body weight on the man's neck until an ambulance arrived minutes later and Floyd was loaded onto a stretcher showing no signs of life.

He was later pronounced dead at a local hospital.

The FBI has launched a criminal investigation into the case, which has sparked strong reaction across the country.