Japan's export growth slowed for a sixth straight month in August, in a sign that the recovery is losing steam.
August's 15.8% annual rise in exports was well down from a peak in February, when growth rose to 45.3%.
The August slowdown came as the yen approached a 15-year high against the dollar, and led to Japan's central bank intervening to weaken the currency.
Japan is also worried that a deepening territorial row with its biggest export partner, China, will also hurt growth.
The Japanese trade figures show that US-bound exports rose 8.8% from a year earlier, but were much weaker than the 25.9% rise in July.
Exports to Asia, which account for more than half of Japan's total exports, rose 18.6% from August last year, slower than July's increase of 23.8%.
Exports to China were up 18.5% in August from a year earlier, down from a 22.7% annual increase in July.
Japan's fragile recovery continues to worry analysts. "We still face the risk of a double-dip recession," said Takahide Kiuchi, chief economist at Nomura Securities in Tokyo.
Japan's export-led recovery has been constrained by the strong yen, which makes goods sold abroad more expensive and reduces the value of profits repatriated.
Japan's central bank has twice intervened in the currency markets in the past two weeks, selling yen and buying dollars to bring down the value of the currency.
But Japan's export problems are not helped by a dispute with China over the arrest of a Chinese trawler skipper whose boat collided with a Japanese patrol ship.
Chinese customs offices have started stricter checks on shipments to Japan, causing severe delays in the delivery of goods.