London (CNN) -- British Transport Police are not commenting on reports that it has beefed up security presence at subway stations and airports after new information emerged about the possibility of an attack being planned in or near London.
"We don't have armed officers in our stations," the agency said Friday. "We have been briefed about how to respond to a Mumbai-style gun over the last few months. We don't comment on deployment of officers but I can tell you that we haven't cancelled any leave".
Several media outlets in England, citing anonymous security officials, had reported a stepped-up police presence in response to the potential threat.
And a British security source told CNN on Thursday that increased security precautions have gone into effect at train and subway stations and Heathrow Airport, though an attack is not considered imminent.
Neither the Home Office nor the transportation department would comment about security measures.
The action is not connected to terrorism arrests last month in Stoke, Cardiff and London, another source said. CNN
