Manhunt under way in London after bomb detonated on packed underground train

A manhunt was launched yesterday after a bomb was detonated in a terror attack on a packed London Underground train.

Witnesses described scenes of terror and panic as the blast sent a "fireball" and a "wall of flame" through a District line service at Parsons Green station in west London.

Police suspect the explosion was sparked when an improvised explosive device was detonated, and have launched a huge counter-terrorism investigation alongside MI5.

The device is being forensically examined while detectives are scouring CCTV and examining witness statements for potential leads.

London Mayor Sadiq Khan told LBC radio "there is a manhunt under way as we speak", while Scotland Yard said detectives are making "fast-time" inquiries to establish who was responsible, adding that there have been no arrests.

Prime Minister Theresa May condemned the "cowardly attack", saying it involved a device "clearly intended to cause significant harm".

As Britain faced up to another terrorist incident, following four attacks already this year:

The Prime Minister said the terror threat level would remain at severe - meaning an attack is highly likely - but would be kept under review; images emerged on social media appearing to show wires protruding from a flaming bucket inside a plastic carrier bag on the floor of a carriage; reports suggested the device had a timer.

A total of 22 patients were being treated in hospital as of this evening with a number of those hurt suffering from burns.

Scotland Yard and the PM rebuked US President Donald Trump over his claim the Parsons Green Tube bomber was "in the sights" of Scotland Yard.

Police were called at around 8.20am yesteday morning following reports of a fire on the District line train as it pulled in to the station.

Emergency services including armed police went to the scene and cordoned off the station.