Foreign Minister Fumio Kishida welcomed the interim deal reached by Iran and six major nations on curbing Tehran's nuclear activities in return for an easing of sanctions imposed by Western countries.
"We'd like to welcome it as a major first step," Kishida told reporters in the west Tokyo suburb of Fuchu on Sunday, adding that Japan will closely monitor whether the agreement is followed.
Under the deal struck in Geneva early Sunday, Iran will stop uranium enrichment above a fissile purity of 5 percent while halting construction of the Arak research reactor, which is feared capable of yielding potential bomb material.