London- A state of terror prevailed in London Wednesday after a man carried out a terrorist attack near the parliament in Westminster.

The attack, which also coincided with the commemoration of last year’s ISIS attacks in Brussels, started when a man, still unidentified, used his car to strike pedestrians on Westminster Bridge before crashing into the railings surrounding the heavily guarded Houses of Parliament.

The attack left at least four people dead and more than 20 injured, according to local authorities.

The assailant then ran through the gates brandishing a knife and stabbed a 48-year-old policeman to death before being shot dead by another officer.

Immediately after the attack, police officers closed the Parliament complex and MPs who were inside the House of Commons were asked to stay there. They were later escorted by armed policemen to the nearby Scotland Yard offices.

UK Prime Minister Theresa May was in parliament at the time of the attack and was seen being ushered away in a silver car as what sounded like gunfire rang out. At night, May chaired an emergency cabinet (Cobra) meeting.

She described the attack as “sick and depraved.”

The British PM said: “We will all move forward together, never giving in to terror and never allowing the voices of hate and evil to drive us apart.”

Mark Rowley, the Metropolitan Police Service’s assistant commissioner for specialist operations, said in a press conference outside the Scotland Yard offices that an unarmed policeman, three civilians and the assailant died in the attack.

Rowley said police believed there was only one attacker.

The Muslim Council of Britain issued a statement condemning the attack.

“Our thoughts and prayers are for the victims and those affected. We pay tribute to the police and emergency services too for handling the situation bravely,” the Council said in a statement received by Asharq Al-Awsat.

Several countries, including the US, Germany, France and the Gulf Cooperation Council, condemned the attack.

It came a year to the day after ISIS jihadists killed 32 people in twin bomb attacks in Brussels and after a series of deadly assaults in Europe that had hitherto spared Britain.