A suspect package found in a post box at the home of billionaire businessman George Soros contained an explosive device, New York police have confirmed.
The item was discovered on Monday by an employee of Mr Soros, who took it to a nearby wooded area, where it was later destroyed by bomb squad officers.
The incident is being investigated by the FBI's Joint Terrorism Task Force.
Mr Soros has become a frequent target for criticism by right-wing groups due to his support for liberal causes.
Mr Soros was not at his home in the town of Bedford in Westchester County at the time of the incident, according to reports.
"An employee of the residence opened the package, revealing what appeared to be an explosive device," a Bedford Police Department official told the New York Times.
Officials say that police received a call about a suspicious package at about 15:45 local time (20:45 GMT) on Monday.
Arriving at the scene, police discovered a device that was later confirmed by officials to have contained explosive powder and "had the components" of a bomb. It was then "proactively detonated", police said.
The FBI tweeted that it was investigating an incident in the area.
We are conducting an investigation at and around a residence in Bedford, NY. There is no threat to public safety, and we have no further comment at this time.— FBI New York (@NewYorkFBI) October 23, 2018
Police later confirmed that an "extensive investigation" had been opened with the FBI.
Who is Soros?
The 88-year-old Hungarian-American businessman earned his fortune through shrewd financial speculation.
He has spent billions of his own money funding human rights projects and liberal democratic ventures around the world and has been a large donor to the US Democratic Party.
He previously backed the presidential campaigns of Barack Obama and Hillary Clinton, and labelled US President Donald Trump "an imposter".
US-based right-wing conspiracy theorists and websites have accused Mr Soros of secretly engineering a range of recent events in US and global politics.
They have alleged he was involved in recruiting crowds for the anti-Trump Women's March and even organising violence in Charlottesville to undermine the country's political right wing.
Mr Soros has also become a political target worldwide for nationalists and populists, who paint him as a master manipulator of democracy.