Police in Britain say they have arrested a man in connection with a series of letter bombs that injured at least eight people.

A police spokesman said Monday they had arrested a man described only as being in his early 20s in the English city of Cambridge, about 65 kilometers north of London.

He also said they can not rule out the possibility that another letter bomb is still within the postal system.

The attacks began in late January. The majority of the explosive devices appear to have been sent to companies that provide services for law enforcement agencies, particularly those dealing with traffic and transportation issues.

Police say they believe the bombs were designed to shock rather than kill or maim their recipients.

Police arrested one man ten days ago after he called a radio station and said he was going to claim responsibility for the attacks. He was held under the country's Mental Health Act.

Some information for this report was provided by AFP, AP and Reuters.