British authorities have conducted a controlled explosion on London's subway system after train staff reported finding a suspicious item on a train travelling eastbound on the Jubilee Line.

The incident took place at 11 a.m. local time (1000 GMT; 0600 a.m. EDT) at the North Greenwich Underground Station. The station, which was evacuated, remains closed.

Specialist police officers from the Metropolitan Police and the British Transport Police were taking part in the investigation Thursday.

Authorities say they have an "open mind," but that the Met's Counter Terrorism Command is leading the inquiry.