Belfast, Northern Ireland (CNN) -- Masked men, allegedly shouting they were members of the Irish Republican Army, abandoned a small bomb and fled a commercial area in Londonderry, Northern Ireland, the mayor said Saturday.
Londonderry Mayor Colum Eastwood, a member of the Social Democratic Party, said the bomb was carried into the office of the Santander bank on Shipquay Street on Saturday by the men who immediately fled the scene. The bomb, which exploded an hour later, did not cause injuries or substantial damage, he said.
Justice Minister David Ford condemned the attack: "This bomb was left in the centre of a shopping area on a Saturday afternoon as people were going about their normal business. It is an attack on the local community and I condemn it wholeheartedly."
Northern Ireland, historically plagued by sectarian violence between Catholics and Unionist Protestants, has seen a resurgence of violence. Londonderry is in the northwest corner of the country, near the border with Ireland.
A cross-community alliance of Catholic and Protestant activists, the Alliance Party of Northern Ireland, expressed "disgust" over the bombing.
In a news release published on Saturday, the Alliance Party's Stewart Dickson said while there were no injuries, he believed the perpetrators were "callous and sick."
"Those behind this explosion had intent to murder a large number of people," said Dickson.
The leadership of Sinn Fein -- the republican political party that seeks for Northern Ireland to become part of the Republic of
Ireland, rather than the United Kingdom -- disassociated itself with the incident.
In a statement Saturday, Sinn Fein Councillor Gerry MacLochlainn blasted those who planted the bomb as being "devoid of any strategy to unite Ireland."
"The people who planted this bomb need to tell the people of Derry how it will contribute to bringing about the new Ireland Republicans are striving for," said MacLochlainn.
The Irish Republican Army, or IRA, fought a bloody campaign against British rule in Northern Ireland for decades before starting a process of decommissioning nine years ago.
Those who refused to accept the Good Friday Agreement that led to the decommissioning are known as dissident republicans, and they include the Real IRA, an IRA splinter group.