The attack coincided with John Major's visit to Belfast but did not appear to be linked to it.
The bomb was left in a stolen car outside the Sinn Fein offices on the Falls Road, at a spot which is close to many houses. Army experts dealt with the device using two controlled explosions, and police said later it contained 50 kilogrammes of home-made explosives, a booster charge and detonating mechanism.
Roy Dunne, a Royal Ulster Constabulary Chief Inspector, said that only the professionalism and expertise of the bomb disposal officers had prevented serious injury and damage.
The period of the general election campaign has seen a sharp reduction in violence from both republican and loyalist terrorist sources, but this attack has obviously revived fears that the relative calm could be shattered.
Loyalist sources and others have said that extreme Protestant groups might well retaliate for the IRA gun attack which seriously injured a policewoman in Derry several weeks ago, but the loyalists have since been almost eerily quiet.
The pattern of recent months has been for loyalists to react with what one source characterised as "measured retaliation" for acts of IRA violence.
It is not known whether yesterday's failed attack means they will consider honour to be satisfied, or whether they will attempt to strike again.
But coming as close to polling day as it has, inevitably means that security at polling stations will be reviewed. Sinn Fein election candidate Gerry Kelly accused the Prime Minister of ignoring the incident. He said: "It is notable that on the day Mr Major visits Belfast he is silent about this incident. This attack was carried out by loyalists who hope no blame will be attached to them because they did not claim it."
Meanwhile, a prison warder was released unharmed after being held hostage for more than four hours at Maghaberry prison near Lisburn, Co Antrim. He was grabbed by two prisoners who brandished what appeared to be two firearms and held him in a cell.
Later the men voluntarily gave up their weapons and surrendered, and were transferred to a segregated unit in the jail. They were said to have connections with a minor republican organisation, the Irish National Liberation Army.Reuse content