Shooting of N. Ireland police officer 'devastating'
STORY: Two gunmen shot the off-duty officer a number of times at a youth sports complex on the outskirts of the town, the Police Federation for Northern Ireland, the representative body for officers, said in a statement.
Police in the Republic of Ireland said they were assisting the PSNI and had intensified patrolling in counties along the open border with Northern Ireland.
The PSNI did not comment on a motive for the attack.
While a 1998 peace deal largely ended three decades of sectarian violence in Northern Ireland, police officers are still sporadically targeted by small splinter groups of mostly nationalist militants opposed to Britain's rule over the region.
Some 3,600 people died during the fighting between Irish nationalist militants seeking union with the rest of Ireland, and the British army and pro-British unionist militants wanting to stay in the United Kingdom.