A security guard at the US Holocaust Museum in Washington D.C. has been shot dead by an anti-Semitic assailant, who was in turn shot and wounded by other officers.

James Von Brunn, 88, fatally injured Stephen Johns just before 1pm today (10 June) after entering the museum and firing "indiscriminately". Von Brunn was hit in the head by two other security officers. He is said to be in a critical condition.

Von Brunn, a World War II veteran, is reportedly a Holocaust denier and a white supremacist, even writing a book entitled Kill The Best Gentiles.

The museum, which had around 2,000 people inside at the time of the shooting, including school children, released the following statement on its website: "There are no words to express our grief and shock over today's events at the museum, which took the life of officer Stephen Tyrone Johns.

"Officer Johns, who died heroically in the line of duty, served on the museum's security staff for six years. Our thoughts and prayers go out to officer Johns's family. We have made the decision to close the Museum Thursday, June 11, in honor of officer Johns and our flags will be flown at half mast in his memory."