No one was injured in the incident yesterday night but police warned it was part of a "surge" of activity by republican groups opposed to peace in the British province.
Masked men wearing boiler suits hijacked a car, loaded it with a bomb containing about 60 kilogrammes (130 pounds) of home-made explosives and told the terrified driver to go to a shopping centre.
He left his vehicle near the mall car park and raised the alarm, causing police to evacuate hundreds of people from homes, restaurants and a cinema nearby.
"We are viewing this as an effort to try and really disrupt the city centre in the run-up to Christmas," said Assistant Chief Constable Drew Harris.
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"It is many years since we have had such a direct attack in the city centre of such scale, we are asking people to be vigilant. People will see an increased police presence in the city centre."
Police chief Matt Baggott warned the incident was part of an increase in activity by groups who still want the British province to be part of the Republic of Ireland.
"These groupings are trying to bring themselves to notice again. They seem to be in some form of bizarre competition to make sure that they have a profile."
In a similar incident last week, a bus driver was ordered to drive to a police station in Londonderry, to the north of Belfast, with a bomb on board.
More than 3,500 people died during three decades of violence between Catholic republicans and Protestant unionists who want to remain part of Britain.
Baggott said that "99.99 percent of the public are absolutely opposed to anything that will take the province back".