US detectives have foiled a plot to kidnap and kill the teenage singer Justin Bieber – and to castrate two other men with hedge clippers.

Police have charged two men and recovered a selection of tools, as well as a hand-drawn picture of Bieber, a Canadian.

The plot was allegedly hatched by jailed killer Dana Martin, who was obsessed with Bieber and angry that the singer had failed to respond to his letters.

Martin, who has a tattoo of Bieber on his leg, told investigators he persuaded a man he met in jail and the prisoner's nephew to kill the singer, his bodyguard and two others.

Police say the plotters wanted to castrate two of the victims with hedge clippers before travelling to New York city to find Bieber. The targets of the castration plot were not connected to Bieber, authorities said.

Martin, a Vermont man who is serving two life sentences for the 2000 killing of a 15-year-old girl, said he was angry at Bieber over the letters and also frustrated that he was a "nobody" in prison.

He told police that his two accomplices, Mark Staake and Tanner Ruane, headed from New Mexico to the east coast, planning to be near a Bieber concert in New York city after killing and castrating the two other victims.

But they missed a highway exit and crossed into Canada from Vermont. Staake was arrested on an outstanding warrant and Ruane was held later.

Court documents say Martin told investigators Bieber was the "ultimate target".

Staake, 41, faces charges of conspiracy to commit murder and aggravated battery with a deadly weapon. Ruane, 23, Staake's nephew, also faces multiple charges.

Clinton Norris of New Mexico police said Martin instructed the suspects to strangle the first two targets with paisley neckties, the same kind used in his 2000 murder case. The documents do not reveal how they were to kill Bieber.

Bieber's management issued a statement saying: "We take every precaution to protect and insure the safety of Justin and his fans."