Police in New York have been told to be on high alert after officials learned of a possible plot by members of a notorious gang to try and kill on-duty officers.

Police representatives said the New York Police Department had been told about a threat by ten members of the Black Guerilla Family to try and murder one or more officers. The threat comes as New York and others US cities continue to see angry anti-police demonstrations following a recent decision not to prosecute an officer accused of choking to death an unarmed man this summer.

The threat from the Black Guerilla Family (BGF), originally formed inside Californian jails in the late 1960s and which has more recently been active in Baltimore, was reportedly discovered by a secret informant. The New York Daily News said the threat about the gang members, who swear allegiance for life and wear “BGF” tattoos, was being passed on to all officers.

Ed Mullins, President of the NYPD Sergeants’ Benevolent Association, said officers were being warned to take extra precautions, when they were both on and off duty.

“Please WEAR your VESTS and carry your firearm off duty along with additional magazines,” Mr Mullins said in an alert to officers. “Your priority is to go home at the end of your tour.”

In pictures: Protests over death of Eric Garner Show all 30 1 /30 In pictures: Protests over death of Eric Garner In pictures: Protests over death of Eric Garner Eric Garner protests Protesters stand in Foley Square in New York City during demonstration against the chokehold death of Eric Garner In pictures: Protests over death of Eric Garner Eric Garner protests A protestor hold up her hands in front of the NYPD as she and others block traffic on the West Side Highway during demonstrations in New York In pictures: Protests over death of Eric Garner Eric Garner protests Police make an arrest as protesters rallying against a grand jury's decision not to indict the police officer involved in the death of Eric Garner march through Midtown in New York In pictures: Protests over death of Eric Garner Eric Garner protests New York City police officers push people out of an intersection in Times Square In pictures: Protests over death of Eric Garner Eric Garner protests A demonstrator is arrested during a protest following the decision by a Staten Island grand jury not to indict a police officer who used a chokehold on Eric Garner, who subsequently died, in New York In pictures: Protests over death of Eric Garner Eric Garner protests A demonstrator is arrested during a protest In pictures: Protests over death of Eric Garner Eric Garner protests epaselect epa04515471 A woman reacts as New York City police officers push people out of an intersection in Times Square during a protest against the decision of a grand jury not to indict a police officer involved in the death of Eric Garner In pictures: Protests over death of Eric Garner Eric Garner protests People march toward the West Side Highway during a protest in New York In pictures: Protests over death of Eric Garner Eric Garner protests People march over the Brooklyn Bridge in protest against the decision of a grand jury not to indict a police officer involved in the death of Eric Garner EPA In pictures: Protests over death of Eric Garner Eric Garner protests People gather in front of the Adam Clayton Powell Jr. State Office Buiding during a protest in New York In pictures: Protests over death of Eric Garner Eric Garner protests Police make arrests after protesters rallying against a grand jury's decision not to indict the police officer involved in the death of Eric Garner attempted to block traffic at the intersection of 42nd Street and Seventh Avenue near Times Square in New York In pictures: Protests over death of Eric Garner Eric Garner protests Demonstrators stage a 'die-in' at an intersection during a demonstration against recent grand jury decisions not to indict police officers in the deaths of Michael Brown and Eric Garner, in Boston, Massachusetts In pictures: Protests over death of Eric Garner Eric Garner protests A demonstrator protests recent grand jury decisions not to indict police officers in the deaths of Michael Brown and Eric Garner, at Boston Common in Boston, Massachusetts In pictures: Protests over death of Eric Garner Eric Garner protests Police struggle with protesters as they try to get closer to a building during a protest against the decision by a Staten Island grand jury not to indict a police officer who used a chokehold in the death of Eric Garner, in Boston, Massachusetts In pictures: Protests over death of Eric Garner Eric Garner protests State Police officers guard the State House during a protest against the decision by a Staten Island grand jury not to indict a police officer who used a chokehold in the death of Eric Garner, in Boston, Massachusetts In pictures: Protests over death of Eric Garner Eric Garner protests A protester dressed as Santa Claus holds up his hands while marching during a protest against the decision by a Staten Island grand jury not to indict a police officer who used a chokehold in the death of Eric Garner, in Boston, Massachusetts In pictures: Protests over death of Eric Garner Eric Garner protests Protesters hold up their hands before police as they block traffic on the West Side Highway during demonstrations in New York In pictures: Protests over death of Eric Garner Eric Garner protests The Lower Manhattan skyline, including One World Trade Center, is seen in the background as protesters, demanding justice for Eric Garner In pictures: Protests over death of Eric Garner Eric Garner protests Demonstrators protest a grand jury decision not to charge a New York policeman in the choking death of Eric Garner, in New York In pictures: Protests over death of Eric Garner Eric Garner protests At the start of the march protestors walk down West Market street to Broad street. 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In recent years officials in the US state of Maryland, which includes the city of Baltimore, have linked the BGF to an increasing wave of crimes, including drug-dealing and murder. Earlier this year it was reported the gang was responsible for at least 19 killings since 2006.

The threat to officers come days after a grand jury in Staten Island decided not to charge police officer Daniel Pantaleo for the death of Eric Garner, a 43-year-old father of six who was choked to death in July after being detained by Mr Pantaleo and other officers.

Protests over the circumstances of Mr Garner’s death, along with other incidents in which American police have accused of mistreating and even killing black suspects, have been held in a number of cities including Berkeley, Seattle, Chicago, Philadelphia, Miami and Minneapolis. In Berkeley on Saturday night, one man smashed a grocery store window with a skateboard as others proceeded to steal from the store. At least two other businesses were looted.

However, Mr Mullins, the police officers representative, said he did not think the threat from the BGF was specifically linked to the death of Mr Garner or the decision not to prosecute those officers filmed restraining him and putting in him in a so-called choke-hold, which proved to be fatal.

The protests over Mr Garner’s death came less than two weeks after a grand jury in Missouri declined to indict a white policeman for the shooting dead in August of an unarmed black teenager, Michael Brown.