Belfast fire bomb: Tactic a relic of Troubles
As an incendiary device ignites in a shop in Belfast city centre, the BBC's Ireland correspondent Andy Martin looks at how such attacks were used by republican groups throughout the Troubles in Northern Ireland.
Fire bombs, or incendiary devices, were considered to be relatively low-risk to those who used them, in that they would be abandoned in a busy shop and could be concealed in the pockets of clothing.
They were designed to ignite after shops had closed, thus destroying the premises overnight.
Between 2004 and 2006, dissident republicans set 10 premises alight, most notably in Newry, close to the border with the Republic of Ireland, where four large stores were destroyed by fire.
There has been a recent upsurge in dissident republican activity, and although the impact of some of the attacks has been limited, others have shown what a fine line the police are forced to walk.
Fire bombs are the latest in a line of tactics used at the height of the Troubles by republicans that have re-emerged in recent months - there have been motorway jams caused by hoax bomb alerts, letter bombs sent to senior police officers and hijacked drivers ordered to take bombs to police stations and shopping centres.
Senior officers are faced with having to make decisions about how much security they deploy on the streets, while keeping Belfast and other towns and cities trading without inspiring fear among Christmas shoppers.
Equally, the police are keen to normalise their operations on the streets, and where possible, to move towards a community-policing model.
However, one of the recent attacks was carried out using a Kalashnikov assault rifle, when three police vehicles were struck with 10 bullets in a densely populated part of Belfast.
In such areas, there is little scope for reducing the number of officers armed with rifles, or exchanging armoured Land Rovers for patrol cars.
There are a number of dissident republican groups with varying levels of expertise.
Undoubtedly, some are led by former Provisional IRA members who possess the knowledge necessary to mount serious attacks.
However, they also rely on very young recruits.
Will Kerr, assistant chief constable of the Police Service of Northern Ireland (PSNI) said: "When you look at the capability of people who have the technical knowledge and capability to explode a car bomb, of course we're concerned, but we are also concerned about a new generation of young, active, violent republican terrorists who are determined to keep this campaign going."
Yet, all of the dissident republicans groups lack experienced people at what they would term "operative level".
This is reflected in the sort of attempts made recently to cause disruption. Many of the devices used have either been small, or have failed to fully detonate.
The police had toyed with the idea of releasing a picture of the person they want to speak to with regard to a fire-bomb attack in Belfast city centre at the weekend.
Citing "legal reasons", they chose not to publish the CCTV image. It is believed the suspect may be a minor.
The threat from republicans opposed to the peace process has never gone away.
Security sources had warned that dissident republicans would attempt to increase their activity throughout 2013.
However, increased surveillance by the security services and the PSNI has disrupted a number of planned attacks.
The two agencies appear to be working well together, but no amount of intelligence-gathering can prevent every attack.