Tests on a suspect package found at London Stock Exchange have found it to be harmless.
A Scotland Yard spokeswoman said the package showed no traces of anthrax.
Thirteen Stock Exchange workers were sent to Royal London Hospital as a precaution.
Scotland Yard says a second suspect package recovered from Smith Square has also tested negative for anthrax.
Two people in Belfast were treated with antibiotics as a precaution after they handled another suspect package containing a white powder, it has been confirmed.
It is understood the parcel was sent to their house in the Falls Road area of west Belfast this morning. One of the people alerted the RUC.
The ambulance service and the fire brigade were also summoned.
The Department of Health in Belfast said the powder has been sent to England for analysis.
PA