Belfast (CNN) -- Northern Ireland's leaders condemned Saturday the detonation of a small bomb in central Belfast that police said could have killed or injured people.
The device, left in a holdall bag, exploded at about 7 p.m. local time Friday in Belfast's busy Cathedral Quarter, near St. Anne's Cathedral, police said. No one was hurt.
First Minister Peter Robinson described the attack as "despicable," while Deputy First Minister Martin McGuinness said it showed a "complete disregard for life."
IRA dissidents are widely suspected of being behind the attack.
A warning was telephoned through to a Belfast newspaper, but the wrong location was given for the device, police said.
It was left on a sidewalk by a busy restaurant and the explosion occurred as police were still clearing buildings in the area, which included a hotel, a bar and an arts center.
Chief Superintendent Alan McCrum said anyone nearby when the device went off could have been killed or maimed.
"This was an attack on the people of Belfast going about their normal lives on a busy night for socializing in the city," he said. "Those who carried out this attack have nothing to offer except disruption and destruction."
McCrum appealed for the public to be vigilant in the run-up to Christmas against the threat of further attacks.
More than 1,000 people were affected by the bomb threat and subsequent evacuation efforts, police said.
Police are also investigating reports of fire damage to an office of the Alliance Party. The party last year backed a controversial decision by the Belfast city council to stop flying the Union flag every day, angering loyalists.
In their statement condemning Friday's explosion, Robinson and McGuinness urged anyone with information to contact the police.
"Once again we are witnessing the work of a mindless minority who are intent on taking the heart out of the city and wreaking havoc on the lives and businesses of the people of Belfast and Northern Ireland," said Robinson.
"Their cause will not be progressed in any way by acts such as this."
Northern Ireland's Justice Minister David Ford also condemned those behind the explosion.
"Yet again we see a reckless attempt to kill and injure innocent people in Belfast," he said.
"The people carrying out these attacks have set out no reason and explained no cause for their acts of senseless violence. Their only aim seems to be to injure and disrupt."
Gerry Kelly, a Sinn Fein member of the Northern Ireland Assembly, also condemned what he called an "indiscriminate" attack on the people of Belfast.
"Those that voice support for these groups, (whose) only allegiance is to violence, need to come forward and explain to the people what they aim to achieve by this reckless action," he said.
"They are visionless and opponents of change who will not stop the people of Belfast and beyond from moving forward to a more equal and peaceful society."
Belfast is home to the elected Northern Ireland Assembly, which was established by the Good Friday Agreement of 1998. The agreement largely ended three decades of violence between mainly Protestant loyalists, who want Northern Ireland to remain part of the United Kingdom, and largely Roman Catholic nationalists, who want it to be reunited with the rest of Ireland -- though distrust between the sides remains.
Journalist Peter Taggart reported from Belfast and Laura Smith-Spark wrote in London.