SDLP Policing Board member Conall McDevitt said the murder bid was a "cynical and deplorable act".
Those seeking to target police officers are undermining not only the stated will of the people of Ireland who have long since rejected violence, but also the desire for a new beginning for policing in the North, which is shared by the majority of citizens.
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"My sincerest apologies to everyone who purchased tickets and were planning to come to the upcoming shows."
His comments at the Defence and Security Forum on Monday came after a £20 billion black hole in the budget for the next decade emerged.
The Foreign Secretary said he thinks the health service should be "at the very top of the list" for a windfall after the UK leaves the EU.