POLICE tonight warned firms to be on their guard after a woman was injured in an explosion while opening post at a bioscience company.

The woman suffered a hand injury and was treated at the minor injuries unit at Abingdon Hospital following the incident at Orchid Cellmark, in Blacklands Way, Abingdon.

A second company, in Culham, contacted police after they received a suspect package in the post. The device was not activated and no one was hurt.

Police said the two incidents were being linked and animal rights extremists are suspected.

Bomb disposal officers were called to the firm and a number of people were evacuated from the area following the incident at 9.15am. The area was declared safe at 2pm.

Detectives said they believed there was a strong possibility that the device received by a company was sent by animal rights extremists.

A police spokesman said: "The device has been sent for forensic examination but a reference to a well-known animal rights extremist, Barry Horne, on the back of the envelope, leads officers to make this a priority line of enquiry.

"Horne died in 2001 after becoming ill as a result of a hunger strike. Serious offences have been committed and claimed in his name in the past."

The spokesman added: "Police are warning companies and individuals to be vigilant when dealing with incoming mail. If you receive a suspect package, do not handle it any further and contact the police immediately."

The construction of a new Oxford University animal testing laboratory in South Parks Road has prompted a number of attacks on businesses and sports facilities by animal rights activists.

In November, activists claimed responsibility for a firebomb attack which caused £250,000 of damage to lorries at Deans Farm egg farm in Standlake.

According to the Orchid Cellmark's website, the firm provides DNA testing services for food safety and selective trait breeding, and has laboratories in the United States and the UK.