Fortescue MetalsGroup Ltd. is paying down a further US$577 million worth of debt, whichwill reduce the Australian iron ore producer's interest payments by US$48 millioneach year.

The company has issued a voluntary redemption notice to holdersof its 8.25% senior unsecured notes due in 2019, according to an April 27 news release.

Fortescue plans to redeem the outstanding notes in full usingexisting cash on hand on June 1.

"Today's announcement brings the amount of debt Fortescuehas repurchased in the last 12 months to US$1.7 billion, with our total debt repaymentsin the last two and a half years now exceeding US$4.8 billion," CFO StephenPearce said.

"As previously flagged, we will continue to repay debt usingaccumulated cash balances and operating cash flows."

Pearce said earlier in April, following the release of Fortescue'sMarch quarter results,that an improvement in the U.S. debt markets had prompted the ASX-listed miner toagain consider paying down more debt.

The company's net debt at the end of March sat at US$5.9 billion.