Energy Secretary Rick Perry told his Japanese counterpart, Hiroshige Seko, during their talks in Tokyo that the US commitment to environment is unchanged, according to Kazushige Tanaka, a Japanese industry ministry official who was at the talks.
Perry's comment comes days after President Donald Trump announced the US would withdraw from the Paris accord, a decision that has triggered international disappointment and criticism.
Perry said America, as it has led the effort in tackling carbon reduction and clean coal technology, will continue to be a leader in developing clean energy and its technology.
Japan had little previous experience of decommissioning a nuclear plant, even one that operated normally, so the country has been learning from the 1979 accident at Three Mile Island nuclear plant in Pennsylvania. Its damaged reactor was mothballed but the other reactor is still operating.
Perry yesterday had inspected the Fukushima nuclear plant and offered continuing US support for decommissioning the plant, which is expected to take decades.