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One of the world's biggest solar panel manufacturers, Suntech, says it has defaulted on $541 million in payments to bondholders after a downturn battered the global industry.

The announcement Monday by Suntech Power Holdings Ltd. was a severe setback for one of the renewable energy industry's most successful companies.

Suntech CEO David King said in a statement the company was "exploring strategic alternatives with lenders and potential investors" but gave no details.

Suntech and other solar equipment manufacturers have been hit hard by a price-cutting war and a plunge in global demand.