LONDON — Four people were killed and 20 others were wounded Wednesday in a terrorist attack at Britain’s Parliament that sent crowds of tourists and lawmakers running for their lives.

The victims included a police officer who was stabbed at the House of Commons and died despite the efforts of doctors and a passing government minister to save him.

FOUR dead and 20 injured – including French students and Korean tourists – as terrorist mows down people on Westminster Bridge before being shot dead seconds after murdering a police officer inside Parliament gates

• Four-wheel drive was driven over Westminster Bridge knocking down pedestrians this afternoon
• Victims were said to have been left scattered in the road, with one woman knocked into the River Thames
• Emergency services  treated at least 20 injured people on the bridge, with one woman dead under a bus 
• ‘Asian’ knifeman got into the grounds of Parliament where he stabbed and killed a police officer
• The ‘middle-aged’ attacker was then shot by armed officers and died after being taken to hospital
• Police believe attacker to be a ‘lone wolf’ as confirmed by Prime Minister Theresa May tonight
• Parliament was suspended and the Prime Minister was rushed from the scene in her official car

Twelve people were treated for “serious injuries” at hospitals, and eight others were treated for less serious injuries at the scene, said Pauline Cranmer, deputy director of operations for the London Ambulance Service.

What we know

• An attacker struck pedestrians on London’s Westminster Bridge and then crashed near Parliament.
• A man armed with a knife tried to enter Parliament. He stabbed and killed a police officer before he was shot and killed by police.
• Twelve people were treated for serious injuries. Eight others suffered less serious wounds.
• Police said the attack, which came on the first anniversary of the Brussels terrorist attacks, was terrorism.
• Prime minister, London mayor vow Britons will not be intimidated.
• President Donald Trump promises full assistance to Britain.
• Counterterrorism police sent to British offices and institutions in New York City.

Two other victims were struck by a 4×4 vehicle that plowed into people walking on nearby Westminster Bridge. Some of the pedestrians suffered “catastrophic” injuries, doctors said. A woman was pulled alive from the River Thames below the bridge with serious injuries.