Police have warned companies and the public to take care opening post after another letter bomb injured a woman.
Police have warned firms and the public to take care opening post after another mail bomb exploded in Swansea.
Three women sustained minor injuries in the incident at the main Driver and Vehicle Licensing Authority building.
Seven devices have been received across the UK in the last three weeks with six people receiving minor injuries.
Seven devices have been received across the UK in the last three weeks with six people receiving minor injuries.
The most recent incident involved a woman injured during an explosion in the main DVLA centre in Swansea.
The attack in Swansea, at 0923 GMT is the third of its kind on motoring-related companies this week.
The attack, at 0923 GMT, is the third of its kind on motoring-related companies this week.
A Berkshire accountancy firm was hit on Tuesday, and the London congestion charge operator Capita on Monday.
Police are also investigating a letter bomb which injured a 53-year-old man at his home in Folkestone, Kent, on Saturday.
Detectives are also examining whether there is any connection to three letter bombs sent to companies in Oxfordshire and the West Midlands area last month.
In those cases, the companies received an A5 jiffy bag containing a crude firework-type explosive device.
"Can I express my sympathy to all those who have been caught up in those incidents Tony Blair
The investigation into the seven letter bombs is being co-ordinated by Acpo's National Co-ordinator for Domestic Extremism (NCDE), Assistant Chief Constable Anton Setchell.
The investigation into the seven letter bombs is being co-ordinated by Acpo's National Co-ordinator for Domestic Extremism (NCDE), Assistant Chief Constable Anton Setchell.
He said: "The packages received so far have caused minor injuries, but could have been more serious.
He said: "The packages received so far have caused minor injuries, but could have been more serious.
MAIL-BOMB LOCATIONS 1 Folkestone, Kent - 3 Feb 20072 Capita, London - 5 Feb 20073 Vantis, Wokingham, Berks - 6 Feb 20074 DVLA, Swansea - 7 Feb 2007
"I am appealing today for companies, organisations and individuals to take extra care when handling mail. If they have any suspicions about any letter or package they should leave it unopened and call the police immediately."
"I am appealing today for companies, organisations and individuals to take extra care when handling mail. If they have any suspicions about any letter or package they should leave it unopened and call the police immediately."
The woman injured in the post room of the Driver and Vehicle Licensing Agency was involved in "a small letter-type explosion", South Wales Police said.
Home Secretary John Reid described the incidents as "worrying".
But he added: "It is important we allow police to get on with their investigation without undue speculation."
A cordon has been put in place around the scene of the DVLA blast and access roads have been closed.
Morriston Hospital, where the woman was taken, said in a statement she was in a stable condition.
"She is undergoing treatment at the present time and has been assessed by a consultant," the statement said.
Investigation
On Tuesday a package exploded at the Berkshire offices of an accountancy firm linked to Speed Check Services, based in Camberley, Surrey, the provider of digital speed cameras to the police.
On Tuesday a package exploded at the Berkshire offices of an accountancy firm linked to Speed Check Services, based in Camberley, Surrey, the provider of digital speed cameras to the police.
MAIL-BOMB LOCATIONS 1 Folkestone, Kent - 3 Feb 20072 Capita, London - 5 Feb 20073 Vantis, Wokingham, Berks - 6 Feb 20074 DVLA, Swansea - 7 Feb 2007
That followed a letter bomb attack the day before at the central London offices of Capita.
That followed a letter bomb attack the day before at the central London offices of Capita.
Police are also investigating a letter bomb which injured a 53-year-old man at his home in Folkestone, Kent, on Saturday.
Three letter bombs were also sent to companies in the Oxfordshire and West Midlands areas last month but these are so far not being linked to the latest attacks.
In those cases, the companies received an A5 jiffy bag containing a crude firework-type explosive device.
Can I express my sympathy to all those who have been caught up in those incidents Tony Blair
A cordon has been put in place around the scene of the DVLA blast and access roads have been closed.
A South Wales Police spokeswoman said three people were being treated for injuries after the "small letter-type explosion" in Swansea.
She added: "One woman has sustained minor burns and two other women have sustained hearing-related injuries."
Home Secretary John Reid described the incidents as "worrying".
But he added: "It is important we allow police to get on with their investigation without undue speculation."
Prime Minister Tony Blair told the Commons that the attacks were being investigated "very closely".
He was speaking after Labour's Sian James condemned the attack in her Swansea East constituency.
Mr Blair told her: "Can I express my sympathy to all those who have been caught up in those incidents in your constituency and elsewhere and say how sorry we are that they have been put through what is obviously a very traumatic time for them."
"Appalled"
Peter Power, a former senior officer at Scotland Yard, told the BBC the police would be looking at whether a "disgruntled" motorist could be behind the attacks.
Peter Power, a former senior officer at Scotland Yard, told the BBC the police would be looking at whether a "disgruntled" motorist could be behind the attacks.
"I've got no doubt whatsoever that the police are desperately trying to think about who the perpetrators might be," he said.
"I've got no doubt whatsoever that the police are desperately trying to think about who the perpetrators might be," he said.
"Are they trying to draw attention to a cause, are they or is he or is she just a very disgruntled motorist? So there is some connection and the police I'm sure will be trying to find that out."
"Are they trying to draw attention to a cause, are they or is he or is she just a very disgruntled motorist? So there is some connection and the police I'm sure will be trying to find that out."
Nigel Humphries, from the Association of British Drivers, told BBC Radio Five Live he was "appalled" by the apparent bombing campaign.
Nigel Humphries, from the Association of British Drivers, told BBC Radio Five Live he was "appalled" by the apparent bombing campaign.
He added: "In fact, it makes us feel a bit guilty that we haven't campaigned hard enough on the legitimate front against the things that we oppose, to do with criminalising and bullying motorists and because of our failure to campaign hard enough, somebody's had to resort to this."
He added: "In fact, it makes us feel a bit guilty that we haven't campaigned hard enough on the legitimate front against the things that we oppose, to do with criminalising and bullying motorists and because of our failure to campaign hard enough, somebody's had to resort to this."
In a separate incident on Wednesday, a controlled explosion was carried out on a package found on a road in Havant, Hampshire.
In a separate incident on Wednesday, a controlled explosion was carried out on a package found on a road in Havant, Hampshire.
Police said they were not linking this with the other four letter bombs.
Police said they were not linking this with the other letter bombs.
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Have you been caught up in events? Are you in the area? If you have any information you would like to share with the BBC you can do so using the form below:
