Determined to overturn police restrictions on their march, Protestants attacked police overnight in Belfast with bullets, rocks, gasoline bombs and grenades in the most serious street violence since April's peace agreement.

The British army announced Tuesday it was deploying an extra two battalions of soldiers to Northern Ireland after a second night of widespread protests and mob violence in Protestant districts.The Orange Order, Northern Ireland's conservative Protestant brotherhood, appealed for nonviolent protests only against police restrictions on their annual march last Sunday through the main Catholic section of Portadown, 30 miles southwest of Belfast.

Britain's minister responsible for governing Northern Ireland, Mo Mowlam, urged Orangemen "to recognize that there are sinister elements using their protest to attack the security forces."

The imminent deployment of the first battalions of the elite Parachute Regiment and King's Regiment by plane from England - swelling the combined strength of police and troops here to more than 30,000 - underscored British resolve to quell the mayhem before it turns deadly.

In London, Prime Minister Tony Blair announced he would be "very pleased to meet" an Orange delegation at his London office, probably Wednesday, to hear their demand to be allowed to march past Catholic homes along Portadown's Garvaghy Road.

On Monday night, Orangemen established human blockades across main roads and traveled in a convoy to Hillsborough, a picturesque village midway between Portadown and Belfast, to mount a round-the-clock "Freedom Camp" of protesters outside Mowlam's castle residence.

Police came under rifle fire in three parts of Belfast as they tried to stop drunken youths from hijacking cars and creating flaming road barricades across the city.

In the predominantly Protestant town of Carrickfergus, north of Belfast, people threw 10 grenades at a police barracks and two more into the backyard of a policeman's home. They also gasoline-bombed a bed-and-breakfast where 14 guests were staying.