Nothing had been found yesterday and the search operation was continuing.

A caller claiming to be from the Real IRA said the device was on waste ground and had been fired some time in the previous 48 hours.

However, PSNI area commander Michael Skuce and unionist politicians hit out over the vague details. They appealed for specific information ahead of the school holiday.

Chief Supt Skuce said those who fired the deadly device in an attempt to murder police had no regard for their own community.

He added: "Calling police two days later and failing to provide any useful details as to the location of the device demonstrates the indifference and disregard these people have for anyone but themselves and their own selfish motives.

"Causing disruption and distress to ordinary decent people at this time of year, when people are preparing and looking forward to Christmas, is despicable."

The PSNI warned the public to be extremely cautious and to contact police immediately if they notice a suspicious object or activity.

UUP MLA Tom Elliott said the perpetrators were "reckless" and reiterated a call for limited Army personnel to be deployed.

Arlene Foster, DUP MLA, described the act as "despicable".

"These people have no concerns for children or community; they just want to cause maximum disruption," she said.