Story highlights Attack at the heart of UK's capital is the latest in a series that have turned cars and trucks into ordinary weapons of terror, writes Peter Bergen

Such actions are difficult to prevent

Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of "United States of Jihad: Investigating America's Homegrown Terrorists." This story has been updated to reflect the latest number of fatalities from London Metropolitan Police.

(CNN) It's a depressingly familiar tale. A vehicle slams into a group of pedestrians in a Western city and the terrorist driving the car then uses a knife to inflict further damage and is soon shot by police.

This time it was Wednesday's attack outside one of the most iconic buildings in the world, the Houses of Parliament in London.

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Four victims and the attacker are dead and there are at least 40 injuries. It's the most lethal terrorist attack in the United Kingdom since al Qaeda directed four suicide attackers who killed 52 commuters on the London transportation system on July 7, 2005.

The Parliament attack is just one in a series of such relatively low-tech -- and hard to defend against -- terrorist attacks in the West over the past three years that have typically been inspired by ISIS, and occasionally also inspired by Anwar al-Awlaki, the American-born al Qaeda cleric.

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On November 28, 2016, Abdul Razak Ali Artan, an 18-year-old legal resident of the United States whose family was originally from Somalia, used a car to mow down a group of people at the Ohio State University. Artan then attacked the crowd with a knife. He injured 11 people before he was killed by a police officer.