UN chief Ban Ki-moon on Monday pledged the world body's solidarity with Japan after its quake, tsunami and nuclear disaster and encouraged radiation evacuees to "hang in there". Travelling in the disaster-struck northeast, Ban became one of the most senior foreign leaders to visit the region close to the crippled Fukushima Daiichi atomic power plant, which is still leaking radiation. "I came here to express my solidarity, the United Nations' solidarity for the government of Fukushima, and particularly for affected people in Fukushima," Ban told prefectural governor Yuhei Sato. "Particularly this Fukushima Daiichi nuclear power plant accident has given us great lessons," he said. "We need to carefully review to improve our safety and improve our capacity tools in such an emergency response."