“Nuclear plants are like time bombs,” a former prime minister of Japan has declared.

Speaking Tuesday, Junichiro Koizumi, who held the office from 2001-2006, said the plants “are never safe” when they are located in a country with earthquakes or active volcanoes, Koydo News reports.

Once pro-nuclear, Koizumi changed his stance after the 2011 Fukushima nuclear disaster and has become an outspoken critic of nuclear power, declaring in 2013 that “zero-nuclear policy. . . can be achieved,” and that sitting Prime Minister Shinzo Abe “should use the power given to him to do what the majority of the people want”—ditch nuclear power.

Another former prime minister, Morihiro Hosokawa, has joined with Koizumi to challenge Abe’s pro-nuke stance, and last year the pair launched the Japan Assembly for Nuclear Free Renewable Energy.