Cars were set alight in the street by rioters

The school, where sectarian protests flared last September, closed on Wednesday after trouble erupted in the area, prompting violent riots.

Parents of pupils at the school welcomed the governors' decision on Thursday, saying their children must continue their education.

Loyalists in the area said there would be no repeat of last summer's protests.

Nationalist and loyalist communities have blamed each other for the two nights of rioting, but youths from both sides were out in force.

Meanwhile, rioters from both sides clashed in the Whitewell area of north Belfast as police were dealing with the trouble in Ardoyne.

Schools targeted

During pitched battles in Ardoyne on Thursday night, a soldier was hit in the face by an acid bomb.

Police fired seven plastic bullets at the crowds, and 11 arrests are believed to have been made.

Two blast bombs exploded among police as they confronted the crowds in the Ardoyne area.

We are going to resist the pressure we are coming under to have any sort of protest, and we are calling on people to remain calm

Community worker Mark Coulter

Army bomb disposal experts made safe three devices which failed to explode when they were thrown at police lines by nationalists.

Nearby, about 60 loyalists confronted troops at Twaddell Avenue where the soldier was injured by an acid bomb.

Schools were also targets of aggression - earlier on Thursday a group of men entered a Catholic secondary school and smashed 17 vehicles in the car park as pupils looked on.

Protestant pupils at another school were driven home in armoured police vehicles.

The violence follows riots on Wednesday in the Ardoyne Road, Crumlin Road and Brompton Park areas which left 48 officers injured and four civilians suffering wounds from gunshot pellets.

An argument between two women is believed to have been the spark that triggered the rioting.

Last year police had to escort parents and pupils to Holy Cross school

First Minister David Trimble described the scenes in north Belfast as depressing.

He said the trouble was obstructing efforts to set up a community forum aimed at improving the situation on the ground.

Measures would be discussed with community activists on Friday, he said.

"We're prepared to put resources into mediation if mediation is going to be the way in which we get that forum into existence," he said.

But the extent of the increased tension was voiced by residents of Upper Ardoyne who accused nationalists of trying to provoke them into resuming their protest at Holy Cross School.

Parents' choice

Community worker Mark Coulter, who attended a meeting of the Glenbryn residents committee and political representatives on Thursday, called on police to step up security.

"People are very, very clear that they are not going to be used as political pawns by anyone," he said.

The chairman of the board of governors at Holy Cross, Father Aidan Troy, said the decision to re-open the school on Friday had been taken on Thursday night in the "interests of staff and pupils".

"The board has come to the conclusion, hopefully rightly, that the sooner we get the children back into a settled situation the better," he said.

"It could even have a calming effect on the whole situation here."

He said it was up to parents to decide if they wanted to send their children to school.