UPDATE: The Metropolitan Police in London has stood down.
According to CNN, police have not located any trace of any suspects, evidence of shots fired or causalities. Nearby Oxford Circus & Bond street underground stations have now reopened.
LONDON- British police say they are responding to reports of an incident at Oxford Circus subway station, one of London's busiest.
British Transport Police tweeted Friday afternoon that officers are on the scene.
At about 16:38 we started to receive numerous 999 calls reporting shots fired in a number of locations on #OxfordStreet & at Oxford Circus tube station. Given the nature of the info received we responded as if the incident was terrorism, including the deployment of armed officers— Metropolitan Police (@metpoliceuk) November 24, 2017
Witnesses on social media report people running into nearby shops and pubs.
Transit authorities say the station is being evacuated.
This is a developing story. Check back for updates.