A crudely-made improvised nail bomb partially exploded after it was thrown at a house in Belfast, police said.
It happened just before midnight in the Bloomfield Road area in the east of the city on Friday.
Detective Sergeant Rory McPhillips said: “When officers arrived at the scene, we discovered that it was in fact a crudely-made, improvised explosive device (IED), packed with nails. It had been thrown at the house along with a number of fireworks.
“The device had partially exploded, scattering nails and shrapnel across the garden. A woman, who was in the house at the time, was not injured but was left shaken.
“Nearby residents were not evacuated, but were asked to stay at the rear of their properties until Ammunition Technical Officers (ATO) made the device safe."
The officer added: “We would particularly like to hear from anyone who saw two males riding mountain bikes in the area around the time of the incident. We believe they may have information that could help our investigation.
“They are described as being on dark-coloured bikes and wearing dark clothes with their hoods up and faces covered. They may also have been wearing workmen’s gloves. They were seen riding off towards the Grand Parade area.
“Anyone who witnessed any suspicious activity in the area around the time of the attack should contact detectives at Musgrave by calling the non-emergency number 101, quoting reference number 1633 of 18/5/18. Alternatively, information can also be provided to the independent charity Crimestopppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.”