The Social Democratic headquarters in Copenhagen remains cordoned off following the receipt yesterday of an envelope containing a powder, and will remain so until experts have finished analysing the material later this morning.

The envelope, which had no return address, contained an article from an Iranian exile publication and about a teaspoonful of powder.

Tests have shown that the powder was not anthrax or some other toxic material, but the authorities have decided to keep the building closed until analyses have been finalised.

According to the police, the letter was posted in Copenhagen on August 24 and did not contain any direct threats.