Japan Airlines Corp. announced Tuesday it had an operating loss of 5.8 billion yen for the first three quarters of its business year to March, a huge setback from the 800 million yen loss the previous year.

The nation's top airline continues to struggle with a high cost structure that makes it vulnerable to rising fuel prices. JAL said the higher fuel prices cost it 320.4 billion yen in the April-December period -- 36.3 billion yen more than the year before.

JAL had a net loss of 9.3 billion yen for the period -- an improvement from the 23 billion yen loss it had the previous year -- as it had one-time gains from unloading some of its assets.