A drone crashed at the US Open on Thursday, causing a match to be interrupted after it flew over the Flushing Meadows complex.
The done crashed in the corner of the Louis Armstrong Stadium in the latter stages of a women's singles clash between Italy's Flavia Pennetta and Monica Niculescu of Romania.
"At approximately 8:27pm on Thursday, a drone flying from the east flew into the southwest corner of Louis Armstrong Stadium during the Flavia Pennetta vs Monica Niculescu match," said a tournament spokesman.
"No spectators were in the immediate area of the crash and there were no injuries.
"The New York Police Department (NYPD) responded and is conducting an ongoing investigation."
There was a similar incident at Wimbledon in July as some of the world's top players warmed up for the Grand Slam in south-west London.
Police were alerted to a man flying a drone over the All England Club from a nearby golf course in contravention of British law, which states that it is an offence to fly a drone within 50 metres of a structure.
Drones have become a security concern at major sporting events since October, when a Euro 2016 qualifier between Serbia and Albania ended with the match abandoned after a drone carrying a political banner was flown into the stadium.
Players clashed when the drone and flag were pulled to the ground and the Albania players refused to play on after being attacked by Serbian fans.
Also last year, a suspected drone pilot was arrested after a device was flown over Eastlands during Manchester City's Premier League match against Tottenham.