Police said the arrests were made in London, Liverpool and Brighton over a “disruptive and damaging stunt”.
Six people have been arrested on suspicion of a plot to disrupt the London Stock Exchange.
The Met Police said information suggested activists from the Palestine Action group were intending to target the exchange on Monday,
The force said it was believed those involved were planning to cause damage and “lock on” in an effort to stop the building opening for trading.
Arrests were made in London, Liverpool and Brighton on Sunday.
All six people are currently in custody.
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