The 1983 U.S. Senate bombing was a terrorist attack that took place at the United States Senate on November 7, 1983, as a protest against United States military involvement in Lebanon and Grenada. The attack led to heightened security in the DC metropolitan area, and the inaccessibility of certain parts of the Senate Building. Six members of the Maoism Armed Resistance Unit, also known as Resistance Conspiracy, were arrested in May 1988 and charged with the bombing, as well as related bombings of Fort McNair and the Washington Navy Yard which occurred on April 25, 1983, and April 20, 1984, respectively.