Police Say Lone Assailant Among Four People Dead After Attack Near UK Parliament

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Update (2:11 PM EST):

An update from Scotland Yard just after 2pm EST included news that four individuals are and approximately 20 injured after an attack that began with an automobile on Westminster Bridge and ended with a knife attack against a police officer and one assailant being shot by law enforcement near the Parliament building.

In addition to two unidentified people, police confirmed that one of their own officers was among the deceased and that the attacker--who police said appeared to be the lone attacker at the scene--was also killed.

BBC reports:

Mark Rowley, assistant commissioner of the Metropolitan Police, said the police were "satisfied at this stage it looks like there was only one attacker".

The man believed to be the attacker is dead, he said.

Four people have died and at least 20 people were injured in the attack.

"Our strength as the city depends on our ability to stand together at such a terrible time," he said.

Earlier:

A police officer has reportedly been stabbed and his assailant shot by officers near the British Parliament on Wednesday, in what law enforcement officials said they are treating as a "terrorist incident until [they] know otherwise." The Guardian is providing live updates here.

The officer was stabbed at the House of Commons in central London, and there are also reports of a car ramming into people on the Westminster Bridge before driving into the gate outside of Parliament.

Parliament is on lockdown as an investigation gets underway. Dozens of MPs remain in the House.

Guy's and St. Thomas' hospital in Westminster is also reportedly locked down.

Law enforcement officials said no intruders were in the House of Commons and that two people were at least temporarily detained on Westminster Bridge.

As the Guardian's Peter Walker reports, "After giving urgent medical attention to two injured people in Old Palace Yard--including CPR--medics have taken away one person in an ambulance. Another person remains prone on the cobbles, covered completely in a blanket. It seems certain they are dead. It is not known who the two people are, police, a potential attacker or attackers, or others."