A car bomb has been left outside the Policing Board headquarters in Belfast, though it has done no serious damage.
The 400lb car bomb partially exploded and the back of the vehicle caught fire, with two men seen escaping.
Chief Constable Matt Baggott said: “It does appear to be a device that has partially exploded, around 400lb.
“It is a reckless act not just in doing damage but also the potential loss of life.”
A car was found burned out nearby in the staunchly Republican New Lodge area of the city and police are investigating whether there was any link.
Mr Baggott added: “This attack is an attack on the well-being of everybody in Northern Ireland, this is not about an attack on policing or the Policing Board, this is an attack on young people and young people’s future.”
Meanwhile, four people have been arrested after police exchanged gunfire with suspected dissident Republicans in County Fermanagh, Northern Ireland.
The incident took place close to the border with the Irish Republic in Garrison. It is understood that the incident was an attempt to kill a police officer who lives in the village.
Mr Baggott said that officers fired two warning shots, which are being investigated by Police Ombudsman Alan Hutchinson.
He added that his officers had been fired at during the exchange.
Northern Ireland Secretary Paul Goggins said: “When attacks like these happen it brings people together with the strong message that these dissidents will not succeed.
“Policing will continue in Northern Ireland and progress will continue.”
The Policing Board is made up of independent members of the community and politicians who hold police to account through regular public meetings.
