The mayor of Nagasaki City says he has decided not to invite the Israeli ambassador to Japan to the annual ceremony marking the US atomic bombing of the city.

Mayor Suzuki Shiro explained his decision at a news conference on Monday.

He said he made a difficult decision in light of the dire humanitarian situation in the Gaza Strip, as well as how the crisis is being viewed by people across the world.

Suzuki said he cannot rule out the risk of unexpected incidents at the August 9 ceremony. He said the aim of the event is to mourn atomic bomb victims, so he cannot tolerate any disruptions.

He also said that he will instead send to the Israeli envoy a letter calling for an immediate halt to violence in Gaza.

The mayor said the city will send a letter of invitation to the Palestinian envoy to Japan as usual.

Attention had been on Nagasaki, after the city of Hiroshima decided to invite the Israeli ambassador to its peace memorial event this year.

Nagasaki City will send a letter of invitation to a total of 154 countries and territories. Officials say Russia, which continues its invasion of Ukraine, and Moscow's ally Belarus have also been left off the city's invitation list.