Shotgun cartridge posted to Mary Harney's office

Gardaí are investigating a letter containing a shotgun cartridge which was posted to Health Minister Mary Harney.

A Department of Health spokesperson confirmed today that the letter was sent to Ms Harney's office in Hawkins House at the end of last month.

Taoiseach Bertie Ahern told reporters in Dublin that another of his colleagues also received a similar threat, but he refused to provide further details.

Identical letters are also reported to have been sent to a number of fertility clinics around the country.

A group calling itself the Irish Citizens Defence Force is believed to be behind the threat.