HOUSTON (Reuters) - Financial firm Elliott Investment Management's conditional offer for shares was accepted by a U.S. court officer overseeing an auction that will determine the future ownership of Venezuela-owned oil refiner Citgo Petroleum, sources said.

Elliott's offer for shares in Citgo parent PDV Holding is subject to the Delaware court's resolution of claims by a group of holders of defaulted Venezuela bonds, the sources said.

Their claims are threatening to derail the sales process that has already been delayed five times. The value of Elliott's offer could not be immediately learned.

The Delaware court has not disclosed the outcome of its second-bidding round for the PDV Holding shares.