Tension was last night mounting in the North as nationalists prepared to protest at Apprentice Boys' marches in Belfast and Derry today.
The RUC Assistant Chief Constable, Mr Alan McQuillan, who will have up to 1,000 police and troops available, said: "It is a bleak picture, which I hope will not be fulfilled. I hope it can be avoided."
Mr McQuillan said: "I have no doubt whatsoever, based on intelligence which is confirmed by information from community leaders, that extremists intend to orchestrate widespread violence, including the use of petrol bombs. Some of these have been stockpiled and supplies are being added to."
If the extremists get their way, he claimed, "the decent law abiding people of the city could once again find their streets strewn with burnt-out vehicles, shops and offices subjected to firebombing and people put at risk of maiming or death."
After an anti-march rally on the Lower Ormeau Road last night the participants voted for a sit-down protest at today's march. Mr Gerard Rice, of the Lower Ormeau Concerned Citizens (LOCC), said: "Tony Blair can send his stormtroopers to remove us if he wants to."
Political and church leaders had earlier appealed for calm on both sides, saying it would be an insult to the memory of the Omagh bomb victims if the first anniversary of the explosion was marred by violence. Attempts to reach a compromise on the marches were still continuing.
Shop windows have been boarded up in Derry and convoys of British army vehicles, among them personnel carriers and military ambulances, were seen being driven into the city along the main Limavady Road yesterday.
A small group of Apprentice Boys is due to walk down the lower Ormeau at around 8 a.m. before boarding a bus for the main parade in Derry. Up to 10,000 Apprentice Boys are expected to march through Derry city centre. The Bogside Residents' Group yesterday offered to cancel its protest in Derry if the Apprentice Boys agreed not to march down the lower Ormeau. Sinn Fein urged an acceptance of the deal.
Sources in the Apprentice Boys in Belfast last night said they were determined to walk down the road, but were coming under immense pressure to compromise.
The Church of Ireland Bishop of Derry and Raphoe, Dr James Mehaffey, said: "My plea would be that both sides, in the Ormeau Road and Derry, would be willing to take a step in the direction of each other. Too much is at stake and the situation is far too serious with its potential for violence and injury, not to do something."
The Catholic Bishop of Derry, Dr Seamus Hegarty, said the right to march must be balanced with the duty to exercise that right in a "responsible and mature way".
The Security Minister in the North, Mr Adam Ingram, said: "This is a traumatic time for the people of Omagh and, indeed, for all touched directly and indirectly by the terrible events of last year.
The Sinn Fein Assembly member, Mr Martin McGuinness, who visited the lower Ormeau yesterday, said he was deeply disappointed with the Parades Commission's approval of both marches.
The 32-County Sovereignty Movement called for support for nationalist residents' protests. A spokesman for the group, Mr Rory Dougan, said the decision to allow the parades showed yet again that "the British and British rule will always be incapable of giving justice to Irish nationalists".
The Government last night made a last-minute appeal for a "harmonious resolution" to the impasse and expressed its "regret and concern" that local agreement has not been reached.