Six British men aged between 37 and 62 were arrested in Amsterdam earlier this month on suspicion of plotting a gangland killing, the Parool reported on Friday.
All but two of the men have been released from custody, police said. The arrests were made following a tip-off from the British serious crimes squad.
Two men were arrested on the street, three after a car chase and one during a raid on a house.
Three automatic rifles, a revolver, pistol and a quantity of ammunition were also seized.
A police spokesman said the arrests, made on June 10, may be part of a war between two gangs from Liverpool, which have already claimed a number of lives, he said.
