A man, believed to be a catholic, was taken to hospital with severe facial injuries caused by a pipe bomb thrown from a loyalist area during clashes between nationalist and loyalist youths on the Limestone Road in north Belfast today.
More than 20 RUC officers were treated for injuries during the disturbances with to six blast bombs launched at police and army lines during fighting which continued throughout the day.
As the RUC questioned a 32-year-old woman about the loyalist blast bomb attack which left an 18-year-old British soldier critically ill, fresh trouble broke out in the city.
A total of 23 officers were wounded, with several security force vehicles damaged during the disorder.
Army bomb disposal experts also carried out a controlled explosion on a crude device discovered at nearby North Queen Street.
The violence flared as a Welch Fusilier remained in a critical condition in hospital.
He suffered lower body injuries when troops at a checkpoint close to the Holy Cross Primary School in the Ardoyne area of north Belfast came under attack from loyalist crowds hurling petrol bombs and other missiles on Friday night.
An RUC spokesman confirmed: "One person is being questioned by police in connection with the attempted murder of a soldier."
Police and army chiefs have blamed the loyalist Ulster Defence Association for the attack.
The wounded soldier, from Wales, was rushed to the city's Royal Victoria Hospital where a spokeswoman today said he remained in a critical condition.
Meanwhile, six police officers were injured during a republic protest at an army watchtower in south Armagh.
As demilitarisation continued at other installations in response to the IRA's disarmament move, members of Sinn Fein's youth wing tried to break through security fencing at Glassdrumman base near Crossmaglen.
Stones, bottles and fireworks were launched at police in riot gear during the confrontation, an RUC spokesman said.
Angle grinders were also used in a bid to cut down security cameras.
Republicans had gathered at the look-out post to protest that the speed of demilitarisation was not quick enough.
Dismantling work got underway at four army installations last week as part of a rolling programme to scale down the military presence.
RUC Chief Inspector Bob Cargin hit out at those behind the violence and pledged to carry out a full investigation into the events.
Mr Cargin accepted people have a right to protest, but not when it involves violence or criminality.
"The behaviour of the protesters today was disgraceful," he said.
"Police and army were attacked with rocks, boulders and metal spikes, resulting in injury to six police officers, one of whom required hospitalisation."
However, a Sinn Féin spokesman insisted the solution to the problem lay with the Government.
He said: "If the British take their war machine off the top of mountains in south Armagh people would not have to march up and stage these protests."