Japan's top government spokesman on Tuesday said the country was deeply concerned about Iran's latest announcement of a resumption of 20% uranium enrichment.
"The government has strong concerns about this move, which is a breach of a nuclear agreement," Chief Cabinet Secretary Katsunobu Kato told reporters.
Iran’s announcement was in breach of the 2015 nuclear pact with major powers.
Tehran started violating the accord in 2019 in a step-by-step response to US President Donald Trump's withdrawal from it in 2018 and the reimposition of US sanctions lifted under the deal.
The agreement's main aim was to extend the time Iran would need to produce enough fissile material for a nuclear bomb, if it chose to, to at least a year from roughly two to three months. It also lifted international sanctions against Tehran.