The Real IRA has claimed responsibility for trying to kill the families of two police officers.
The group has admitted to three separate attacks in Derry overnight including two attempted bombings and a shooting.
Two of the attacks were attempts to kill the relatives of a serving Catholic police officer in Derry.
The first device exploded outside his parents' home, while a second device was made safe after being found near his sister's home.
In a statement using a recognised codeword, the Real IRA accused the police of harassing republican families.
"If the police," it said, "want to come at us, we will come back at them."
The Real IRA has also claimed responsibility for shooting a man in the legs and hand overnight.
It said he had 24 hours to leave the city once he is discharged from hospital.
There have been six paramilitary-style shootings in Derry in the past four weeks.
This is a significant upsurge in dissident activity and comes shortly after this week's massive bomb find in south Armagh.