Japan PM sent radioactive parcel

Police in Japan have launched an investigation after envelopes containing radioactive material were sent to the prime minister and government offices.

At least one of them included an anonymous message warning that radioactive materials were being sent from Japan to North Korea, a police official said.

PM Yoshiro Mori fears copycat crimes

The envelopes contained about three grammes of a sand-like powder, including a radioactive element thought to be thorium.

But the Kyodo news agency said the level of radioactivity was not deemed harmful.

Thorium can be used in nuclear bombs and nuclear reactors but is also used in a wide array of ceramics and glass processes.

Sinister letter

A total of nine government offices received the mysterious packages, according to Kyodo. They were mailed last week and postmarked Tokyo.

Police official Hajime Kajiwara said the envelope sent to the Education Ministry included a letter warning that "radioactive substance is being sent to North Korea and police should investigate because it is dangerous".

Reports said other departments targeted included the Home Affairs Ministry, the National Police Agency, the Defence Agency, the Science and Technology Agency and the National Public Safety Commission.

An initial examination indicated the substance may be ground monazite, a mineral containing thorium, according to reports.

Mori targeted

Japan's Chief Cabinet Secretary Mikio Aoki confirmed a similar parcel had been sent to Prime Minister Yoshiro Mori on 8 June.

But he said they had not publicised the fact for fear of copycat crimes.

"We believe there is a chance of other copycat crimes so we are not divulging very much. We are leaving everything in the metropolitan police's hands," he added.

Police are also investigating a letter bomb sent to a Tokyo legal firm on Monday not far from major government offices.

The package exploded injuring two employees.

No connection has been made between the two incidents.