A female security guard has been arrested near London's Olympic stadium site on suspicion of possessing explosives, it has emerged.

The 40-year-old dog handler was held after her vehicle was searched in a car park off Pudding Mill Lane on Tuesday, but police said the incident was not thought to be terror-related.

Scotland Yard said the woman was arrested on suspicion of possession of a "very small amount of a substance" that was being forensically examined.

The suspect is currently being held in custody at an east London police station.

The arrest was made by the officers from the Olympic Site Support Unit following information received by police.

Officials said another car was stopped and searched on the M11, but nothing was found in the car, and the driver was not arrested. Searches were also carried out at residential addresses in Kent and London, but no further substances were found.

In a statement the Met insisted that the incident "did not represent a threat to the safety and security of the Olympic site."

A spokesman for the Olympic Delivery Authority said: "There are robust measures to ensure the safety and security of the Olympic Park. We are working with the police in their investigation. At no point has the safety and security of the Olympic Park been put at risk."

A spokesman for G4S, which provides security for the Olympics, said: "G4S take breach of operational processes very seriously and are assisting the police with their inquiries in relation to this incident."

The arrest came on the same day that building work at the £486m Olympic stadium was completed.