Two Northern Ireland policemen and a soldier are in hospital today after a crowd attacked two army watchtowers and besieged Crossmaglen police station.
Twenty-one police officers, three soldiers and two military dogs were injured in the trouble in South Armagh last night.
Two of the more seriously injured police officers were airlifted from the border to hospital with head injuries. One of the soldiers was last night taken to hospital in Belfast suffering from serious burns, police said.
Four people, including two juveniles, all from Belfast, were arrested on suspicion of public-order offences. Police said the violence had been orchestrated and pre-planned.
A crowd of over 100 protesters attacked the Creevekeeran watchtower on the South Armagh border with iron bars, petrol bombs, bottles and fireworks.
Nine police were injured when they tried to stop the crowds from cutting through perimeter fencing.
Police said it appeared the crowds were then taken by bus and car to the neighbouring Drummakavall watchtower where they began a similar attack, injuring 10 officers. Police fired two plastic bullets.
The crowd then moved on and attacked the Crossmaglen police station breaching the main entrance and attacking police and military personnel inside with petrol bombs and other missiles. Three soldiers were injured in that attack.
When the violence ended, the crowds left. Police said one bus load was believed to have returned across the border to the Republic and a second to Belfast.
Mr John Fee, the SDLP Assembly member for the area, condemned the violence and challenged Sinn Féin to say whether it was a new republican tactic in the fight to rid the border of security posts.
He said he had been asking the question since the first protest a month ago and had not been answered. He demanded to know if Sinn Féin's leadership was "hiding behind" its youth wing and if not, "are they out of control?"
It was the second time in a month trouble erupted at what were billed as demilitarisation demonstrations organised by Sinn Féin's youth wing.
PA