Photo-illustration by POLITICO (Source images by Getty Images) London terror attack: as it happened Car hit pedestrians and man armed with a knife attacked police officer.

LONDON — Four people, including a policeman, were killed and dozens injured outside the British parliament in central London Wednesday, in what police are treating as a “terrorist incident.” The suspected assailant was also shot dead in the attack.

At around 2:40 p.m. local time Wednesday, a dark gray car drove across Westminster Bridge towards the Palace of Westminster, hitting a number of pedestrians before crashing into railings on the side of parliament.

Shortly afterward a man armed with a knife continued the attack by charging at the police manning the gates of parliament. He stabbed one officer and was shot dead by police. The officer, later identified as PC Keith Palmer, 48, was killed in the attack.

Two other people killed in the incident — one of whom is a woman in her mid-40s, the other a man in his mid-50s — died on Westminster Bridge. The third, a 75-year-old man, died from injuries on Thursday. A total of 29 people were treated in hospital and seven are in a critical condition. The wounded include three police officers and a number of French schoolchildren.

Police overnight raided six addresses and made eight arrests in connection with the attack.