People in Tokyo have observed the 79th anniversary of a devastating US air raid on the Japanese capital during World War Two.

Some 100,000 people died in the predawn attack on March 10, 1945. Destruction from the US B-29 bombers was focused on the city's eastern residential areas.

On Saturday, about 200 people offered prayers for the victims during a service at a memorial hall in Tokyo's Sumida Ward. They included Crown Prince and Princess Akishino and Tokyo Governor Koike Yuriko, as well as the families of victims.

Ohinata Hiroyuki, the 83-year-old representative of the bereaved families said he lost his grandfather, grandmother and an uncle in the raid. He said it killed many people indiscriminately. He added that 79 years on, he still wants to pass down the hardships caused by the war to young people.

A 93-year-old woman said she lost her brother, who was 20 years old. She said she was truly resentful to lose her loving brother who was so young. She said she has been attending the service every year, and that she wants to pass down the tragic memories to the next generation.