An explosive device was found in the mailbox of investor George Soros' home on Monday afternoon, police said.

Police in northern Westchester, New York responded at 3.45pm Eastern to a call from an employee at the residence, reporting the suspicious package.

A security officer at the compound about 50 miles (80 kilometers) north of Manhattan became suspicious of the package Monday afternoon and placed it in a nearby wooded area before alerting the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives, authorities said.

Agents came out and safely detonated the device, which a federal law enforcement official said contained explosive powder.

'It was not a hoax device,' said the official, who spoke to the Associated Press on condition of anonymity because he was not authorized to discuss the investigation.

Another federal official who also spoke on condition of anonymity said the device resembled a pipe bomb and was inside a package placed in a mailbox outside the gates of the compound.

It was opened in a secure location just inside the gates, nowhere near Soros' quarters, the official said.

Soros was not home at the time.

An explosive device was found outside the home of billionaire investor George Soros, police said on Monday. Soros was not home at the time

Federal investigators are reviewing surveillance video to determine whether the package had been sent through the mail or delivered some other way, officials said, adding it was also not clear if the parcel was addressed to Soros.

Soros, who is Jewish, has often been the target of far-fetched conspiracy theories and racist abuse, mainly from the far-right.

He has been accused by right-wing personalities of turning other Jews over to the Nazis and stealing their riches. In fact, a then 14-year-old Soros and his family were forced to hide from the Hungarian government during the German occupation.

Due to his opposition to Brexit, he was also accused of bankrolling a 'secret plot' to reverse the June 2016 vote in articles which borrowed heavily from antisemitic tropes of Jews conspiring to control the world through money.

Federal investigators are reviewing surveillance video to determine whether the package had been sent through the mail or delivered some other way, officials said; Mailboxes stand outside the entrance to a house owned by Soros in Katonah, a suburb of New York City, in New York

It was also not clear if the parcel was addressed to Soros; The gate is closed at the entrance to a house owned by Soros in Katonah, a suburb of New York City, in New York

Soros, 88, a prominent supporter of the Democratic party which he has frequently funded, has been a target of conservative conspiracy theorists; The mailbox outside his home is shown

The New York Times reported that bomb squad technicians 'proactively detonated' the device.

Federal officials are currently investigating further.

Soros, 88, a prominent supporter of the Democratic party which he has frequently funded, has been a target of conservative conspiracy theorists, Good Morning America reported.

Authorities have not commented on whether any particular group might be more likely to have been involved in this incident.

Recently, conservative critics have, without evidence, accused him of secretly financing a caravan of Central American migrants to make their way north toward Mexico and the US.

Soros is a target of a hostile media campaign by the nationalist government in his native Hungary and a hate figure for right-wing campaigners in eastern Europe and the United States.

Activists frequently post the addresses of homes he owns in Westchester County, north of New York City, on social media sometimes accompanied by ill wishes.

The billionaire business magnate rose to fame and fortune more than two decades ago on a now-historic trade, in which he took on the Bank of England and shrewdly wagered on a devaluation of the British pound.

This led to his moniker - The Man Who Broke the Bank of England.

The move made him $1 billion.

Soros was born in Budapest, studied at the London School of Economics and holds dual Hungarian-American citizenship.

After selling seaside souvenirs he managed to get a foot on the financial ladder with a job at Singer & Friedlander in London in 1954, before settling in the US.

He went on to become one of the richest people in the world through fund management.

As of 2018, his net worth was reported at $8.3 billion.

A security officer at the compound about 50 miles (80 kilometers) north of Manhattan became suspicious of the package Monday afternoon