UN chief Ban Ki-moon on Thursday urged the United States to improve police accountability after protests triggered by a jury's failure to press charges against a white police officer for a black man's death.
Dozens of people were arrested overnight in New York demonstrations after a grand jury decided Wednesday not to indict the police officer involved in Eric Garner's choking death.
The decision came just days after a similar ruling in Ferguson, Missouri sparked riots.
"The case is again focusing on the issue of accountability of law enforcement officials," said UN spokesman Stephane Dujarric.
"The secretary-general urges all competent authorities in the United States to do everything possible to respond to the demands for greater accountability," he said.
Garner's death in July is one of a string of racially-charged incidents in which white police officers have been accused of using unreasonable force or being too quick to fire at black suspects.
An amateur video of the New York arrest shows Garner, a heavy-set man who suffered from asthma and had six children, gasping "I can't breathe, I can't breathe" as police officers held him to the ground.
Ban welcomes the US Justice Department's decision to open a civil rights investigation into Garner's death, said Dujarric.
He also called for demonstrations to remain peaceful following the latest decision.