Japan's exports unexpectedly fell in September — the first drop in almost two years — as natural disasters disrupted economic activity and higher energy prices continued to feed gains in imports.

While one-off events make it difficult to assess the impact of the U.S.-China trade dispute, Japanese export growth has been slowing this year following double-digit expansion in 2017.

In September, Typhoon Jebi temporarily closed Kansai International Aiport — the departure point for around 7 percent of shipments from the manufacturing heartland around Osaka. And an earthquake in Hokkaido cut power to the entire island in Japan's north, disrupting supply chains.