There has been severe criticism from nationalists of the decision of the Northern Ireland Parades Commission to allow Apprentice Boys parades tomorrow in Derry and at the Ormeau Road, Belfast.
From unionists, there were accusations that the nationalist complaints about the decision showed bigotry.
Mr Gerard Rice, of the Lower Ormeau Concerned Community, yesterday refused to rule out a sitdown protest. He said an attempt to block the Ormeau Road was "a very definite possibility".
He accused the Parades Commission of "operating a political agenda and of destroying years of work aimed at reaching accommodation over controversial marches".
A Bogside Residents' Group spokesman confirmed it would be holding a rally in the Diamond at the same time as the Apprentice Boys parade. "Ten thousand loyalists will be laying siege to our city centre for six hours in what is nothing more than a coat-trailing exercise," Mr Donncha MacNiallais said. He described the decision to allow the parade as "reckless and ill-judged".
"We will make every effort to act responsibly. This situation requires cool, calm, disciplined heads, but it won't be easy. I fear a major crisis and possible violence."
Mr Alistair Simpson, governor of the Apprentice Boys, condemned the "veiled threat of violence" from the BRG which he accused of attempting "to hold the Apprentice Boys and this city to ransom". He urged his members to "walk with dignity, pride and respect".
The Rev Ian Paisley, the leader of the Democratic Unionist Party, accused nationalist residents' groups of bigotry and hatred, but said the Apprentice Boys must not be goaded and should "demonstrate to the world the pride and dignity of the Protestant people". Mr Peter Weir, an Ulster Unionist Assembly member, said nationalist groups had shown their "true, bigoted colours".
However, the Ulster Unionist Assembly member, Sir Reg Empey, said: "It was not so long ago that Gerard Rice was urging the government and the RUC to ensure the decision of the Parades Commission was upheld at Drumcree."
Dr Philip McGarry, the Alliance party president, urged nationalists to accept the Parades Commission rulings.