According to reports, a House of Commons spokesperson had previously commented on the situation, saying that the police were investigating an 'incident' on the Parliamentary Estate, but without providing any further details.
When contacted by Arab News, a Metropolitan Police spokesperson said it was "looking into the incident" and that it was being dealt with by specialist officers.
A short statement said: "At approximately 11:36am on Tuesday, 13 February, police were informed of a suspicious package that had been delivered to an office within the Palace of Westminster. Police are at the scene and dealing.
"A letter contained a white powder which is currently being assessed by specialists. The office remains closed at this time, but the rest of the Palace of Westminster is open.
"Detectives from the Met’s Counter Terrorism Command have been informed and are investigating."
A UK parliament statement went on to say that the white powder in the package has been found to be non-harmful, the lower house of the legislature said.
Police were informed of a suspicious package delivered to an office within the Palace of Westminster. Police are at the scene and dealing. The letter contained a white powder which is currently being assessed by specialists.— Metropolitan Police (@metpoliceuk) February 13, 2018
The package is understood to have been delivered to an office below the House of Commons chamber. The UK parliament is in recess this week, however, so the vast majority of ministers are not currently in Westminster.