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LONDON — British police say they foiled an active terror plot after armed police stormed an address in London Thursday evening.

A woman was shot and five people were arrested in the anti-terror raid in the northwest of the city, London’s Metropolitan Police said in a statement. Officials said tear gas was also fired into the property in Willesden, which police said they had been monitoring as part of counter-terrorism operation.

When asked whether police had disrupted an "active plot," Met police deputy assistant commissioner Neil Basu answered "yes," adding that with the arrests police have “contained the threats that they posed.”

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The operation came hours after a man carrying several knives was seized near Britain’s Parliament and arrested on suspicion of planning a terrorist act. Police said the two incidents were unrelated.

Britain remains on high alert after another attacker last month killed five people, including an American tourist and a policeman guarding the Houses of Parliament.

Police said the woman, who is in her 20s, was hospitalized and had not been arrested because of her condition, which they described as “serious but stable.”

Police stand next to a cordon in a residential street in northwest London on Friday after officers shot a woman during a raid. Ben Stansallben Stansall / AFP - Getty Images

Armed police are uncommon in the U.K. but police said the armed raid was necessary “due to the nature of the intelligence that we were dealing with.”

Images from the scene show officers guarding the quiet residential street behind a police cordon. Another suspect linked to the same investigation was arrested in Kent County, southeast of London, on Thursday evening.

The 27-year-old man arrested outside the Houses of Parliament earlier Thursday was held after a stop-and-frisk tied to an “ongoing operation,” police said. Nobody was reported injured in the incident but pictures from the scene appeared to show two knives next to a backpack lying on the ground on a traffic crossing.

"With the attack in Westminster on 22 March so fresh in people’s minds, I would like to reassure everyone that across the country officers are working round the clock to identify those people who intend to commit acts of terror,” said Basu, speaking outside the Metropolitan Police's headquarters. “We are making arrests on a near daily basis."

While relatively few British police officers carry guns, the number of firearms officers around Parliament was boosted after last month's attack. Khalid Masood, 52, killed five people by running them over in a four-by-four before stabbing the police officer to death.

One of those killed was 54-year-old American tourist Kurt Cochran.