British police announced Tuesday that they have opened an investigation into a package containing Uranium after it was discovered by Border Force agents.

On December 29th routine scanning at London’s Heathrow Airport detected the package with small amounts of radioactive material. Officials were quick to note that the package and its content posed no threat to the public and was not believed to be directly linked to any terror threat.

Richard Smith, head of the Metropolitan Police’s Counter Terrorism Command, said in a statement, “I want to reassure the public that the amount of contaminated material was extremely small and has been assessed by experts as posing no threat to the public.” He added, “We will of course follow every avenue to see what the background of this was and satisfy ourselves that there’s no further threat, but I think these are some reassuring messages about what happened.”

Smith also pointed out the success of the screening system and added that no arrests have been made.

The Sun newspaper reported that the package is believed to have originated from Pakistan, coming in on a flight from Oman, and being sent to Iranian nationals living in the United Kingdom. Inside the parcel was a bit of scrap metal, according to the BBC, which had been tainted with Uranium, a naturally occurring element used in energy production and the making of nuclear bombs. However, police have noted the amount of Uranium found on the package is not considered dangerous or “weapons grade”.