Police arrested 45 members of the Hell's Angels (search) motorcycle gang and seized an assortment of weapons during nationwide raids on the group's clubhouses, prosecutors said Monday.

Pre-dawn raids were conducted simultaneously in six Dutch towns and cities and two sites across the border in Belgium following a yearlong investigation, prosecutors said.

Those arrested face charges of murder, extortion, intimidation and weapons and drug trafficking, prosecutors said. Among the items seized were a grenade launcher, a flame thrower, hand grenades, 20 handguns, a machine pistol and more than $80,000 in cash.

Prosecutors said the Hell's Angels used violence, intimidation and extortion to prevent rival motorcycle clubs from opening clubhouses. Tattoo shop owners also have been threatened by the group, they said.

Some of the gang members were also accused of growing marijuana and trafficking in cocaine (search) and Ecstasy (search). Prosecutors said the investigation also dealt with the slaying of a drug dealer and the laundering of $400,000 in drug money last year.