A viable letter bomb has been posted to a senior police officer in Northern Ireland, it was confirmed today.
The package addressed to chief inspector Andy Lemon was intercepted at a sorting office in Strabane, Co Tyrone.
Mr Lemon, who is the area commander in Strabane, described it as a worrying development.
Dissident republicans are being blamed for the attempted attack.
The alarm was raised after postal workers at an office on Castle Street discovered a suspicious package.
A spokesman for the Police Service of Northern Ireland (PSNI) said it was a small viable device which has been taken away for further examination.
The device, which has been described as crude, was made up of a battery pack and accelerant. It was packed into a brown envelope.
Mr Lemon claimed the vigilance of postal staff saved lives.
"It could have gone up at any time," he said. "This was a very dangerous device and I would like to praise the Post Office staff for noticing it. One of them, or one of my officers, could have been injured had they opened it."
The envelope was addressed to Mr Lemon at Strabane police station.
He added: "I do not believe this is a personal attack but more a general attack on the police. Because I am area commander, a lot of mail would come into the police station addressed to myself, but I do not open any of it. That is done by other members of staff. "This was an attempt to kill or injure police."
Mr Lemon said despite the threat PSNI officers would not be deterred from their duty.
He said: "We have a job to do. The threat is severe, it has been severe for some time.. We deal with it daily and do as much as we can to try and minimise that threat."
He said the PSNI were keeping an open mind about who was responsible but acknowledged that dissident republicans were the most likely suspects.
Brian Rea, chairman of the Northern Ireland Policing Board has commended the Post Office staff. "Whilst this has been described as a small device it had the potential to cause injury. Whoever sent this package really didn't care about the harm it could have caused and I praise the vigilance of the postal workers in spotting it."
UUP MLA Ross Hussey, who sits on the Policing Board added his condemnation.
He said: "It is quite clear that so-called dissident republicans are oblivious to the pleas from across the political spectrum that they cease their activities and leave the rest of society to live in peace.
The Police are here to serve and protect the entire community and an attack on one police officer is an attack on all of us."
Northern Ireland's first and deputy first miinisters described the attack as calculated and callous.
In a joint statement Peter Robinson and Martin McGuinness said: "The individuals behind this need to be brought to justice as actions like this have no place in society and those responsible have nothing positive to offer. This was not just a planned attack on a police officer but also on the postal workers involved and society as a whole.
"Violence plays no part in our future. We would appeal to anyone with any information on this to contact the PSNI."
Six roads around the sorting office were closed for several hours from about 10.15am as bomb squad officers carried out their investigations. The security alert has now ended and all roads in the area have been re-opened.
PA