The New York Police Department has marked the upcoming 15th anniversary of the September 11 attacks with a parade to honour its 23 officers who died at the World Trade Center.
Friday's parade through lower Manhattan also commemorated 99 officers who died of illnesses after participating in the rescue and recovery operation. Thirty-seven members of a port agency's police department also died in the attack.
Police departments from across the US and Canada joined the procession.
Bagpipers led marchers around the southern tip of Manhattan, ending near a memorial wall engraved with the names of the fallen NYPD officers.
Police Commissioner William Bratton thanked other police departments for their support. Democratic Mayor Bill de Blasio also attended.
The main September 11 memorial ceremony will take place on Sunday.
