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

Mayor Suzuki Shiro announced the decision at a news conference on Wednesday. He explained that it was not a political decision, but aimed at holding the August 9 ceremony smoothly to mourn atomic bomb victims in a calm and solemn atmosphere.

In June, the city deferred a decision on whether to send a letter of invitation to the Israeli envoy as fighting continued in the Palestinian enclave of Gaza. Instead, the city sent a letter to the Israeli side calling for an immediate halt to violence in the Gaza strip.

Suzuki told reporters that the city had put the decision on hold to ensure the safety of participants and smooth proceedings at the ceremony, given the risk of unexpected incidents and other factors.

The mayor said there are still concerns, nine days before the ceremony.

He added that it was a very difficult decision.

Nagasaki City sent a letter of invitation to a total of 154 countries and territories. Russia, which continues its invasion of Ukraine, and Moscow's ally Belarus are also not on the city's invitation list.

On the other hand, Hiroshima City has sent a letter of invitation to the Israeli envoy for the annual peace memorial ceremony there on August 6.

Israeli Ambassador to Japan Gilad Cohen described the mayor's announcement as "regrettable."

He said in a social media post that the decision "sends a wrong message to the world, and deflects from the core message that Nagasaki has been promoting for years."

The ambassador also wrote, "Israel is exercising its full right and moral obligation to defend itself and its citizens and will continue to do so."