The Mile End tube station in east London was reopened on Saturday after an earlier security alert.

The station was opened after closing for around 30 minutes. Earlier, one witness said he had seen smoke coming from a carriage of the train. A man was reportedly taken away for questioning after police finished the investigation.

London transportation system came across several emergencies in recent days. On Friday morning, a bomber suspect was shot dead at the Stockwell subway station in Southern London as police were intensively hunting for suspects of attempted suicide bombings on Thursday.

Police said two men have been arrested so far under anti-terrorlaws in relation to the failed explosion.

On Friday, the police also issued pictures taken by security camera, of four men they wanted most in connection with the bombings. They were believed to have tried to detonate three bombson Tube and one on a bus.

Source: Xinhua