Two packages containing a powdery substance, which were found in the park area near the Hilton Sofia on Tuesday, do not contain anthrax, according to an announcement by the National Laboratory on Dangerous Infections, which tested the powder. The test of a powder found in a parcel at the Sofia Central Post Office on Tuesday also yielded negative results.

An anonymous man called the Sofia Directorate of the Interior Ministry at 12.40pm on Tuesday and said that the packages had been dropped near the Hilton Sofia. "After the initial inspection of the site, the officers found two small plastic packs with white powder - one on a bench and one in an alley in the park," said a press release from the Interior Ministry.

The same day, the Sofia Central Post Office handed over to the National Security Service a small parcel containing white powder which had been posted abroad, said the executive director of the Bulgarian Post Office, Ventseslav Krustev, on Wednesday. He explained that the wrapping of the suspicious item had been ripped open and a white powder was spilling out. He would not say to which country the package had been destined or whether the recipient was a physical person or an institution.

According to data of the National Police Service, from Tuesday to mid-day on Wednesday, there were 16 signals of packs with white power resembling anthrax found all over the country. By Wednesday, none of the checked substances had turned out to be anthrax, said the press office of the Interior Ministry.

According to a bulletin of the Ministry, police officers in Kyustendil have detained a 38-year-old man who confessed that he had decided to play a joke and dropped a paper pack containing marble powder with a note reading "anthrax" in the region of the local cemetery.

"We are collecting information about all signals from the whole country and the necessary checks are being carried out," said Boyko Hristov, spokesperson of the Ministry of Health.

The National Operative Commission for Emergency Response has determined that there is no need for Bulgarians to purchase the vaccine at this time, the BBC reported on Tuesday after the first regular meeting of the task force of the commission set up last week. Deputy Health Minister Lyubomir Kumanov, who heads the task force, said that the National Centre for Infectious and Parasitic Diseases is to be placed on 24-hour standby.

Specialists will be available to answer telephone inquiries from people and provide advice and information to doctors in case of incidents.