Two men and a woman were arrested at a Sheffield house after police recovered a “crude improvised explosive device” from the property.
Officers were called to a house on Abbey Lane, in Beauchief, on Saturday evening.
A spokeswoman for South Yorkshire Police said: “Two men, aged 28 and 20, and an 18-year-old woman have been arrested in connection with the incident on suspicion of making an explosive device with intent to cause harm.”
The 28-year-old man has been released on bail, while the 20-year-old man and 18-year-old woman have been released under investigation.
Anyone with information should contact South Yorkshire Police on 101 quoting the incident number 883.