ALL Nippon Airways said yesterday that it had swung into a loss for the April-June quarter as it was hit by soaring fuel costs caused by the weaker yen and the grounding of Boeing's 787 Dreamliner aircraft.

The Japanese carrier lost 6.6 billion yen (US$67 million), reversing a small year-earlier profit, despite a 4.4 percent rise in revenue to 358.3 billion yen.

"The primary reason for the increase in operating expenses was a rise in fuel costs due to the weakening yen," it said in a statement. "Operating revenues were also held back by the suspension of Boeing 787 services for part of the period."

ANA and domestic rival Japan Airlines, which reports its quarterly results today, were sideswiped by the grounding of Boeing's new aircraft that began in January. After a long-running probe the planes were allowed to fly again in June.

The carriers at the time operated about half the Dreamliners in service and had to cancel hundreds of flights in the wake of the crisis, which was caused by problems with the plane's lithium battery.

ANA said the Dreamliner crisis had wiped 8 billion yen off its quarterly profit. The carrier and Japan Airlines have said they will seek compensation from Boeing having lost a combined total of more than 22.5 billion yen in revenue.

Kiyoshi Tonomoto, ANA's executive vice president, offered a blunt assessment of the carrier's performance.

"It was a tough result - there is no doubt about it," he told a press briefing yesterday.

But the airline kept its full-year profit forecast unchanged at 45 billion yen, saying Prime Minister Shinzo Abe's bid to stoke the Japanese economy, the world's third-largest, would help its prospects.

Meanwhile, rising competition in the domestic market saw revenue decline 1.3 percent in the latest quarter, but the carrier's international business booked a 7.5 percent rise in sales on the back of steady demand for flights to Europe and North America, it said.