SINGAPORE - Top Philippine oil refiner Petron Corp. bought via tender its first cargo of ESPO Blend crude for delivery in late May or early June, trade sources said on Tuesday, widening the market for the new Russian medium-sweet grade.

The 730,000-barrel cargo was awarded at around a premium of $1.10 a barrel to Dubai quotes, on a cost and freight basis for delivery to Bataan, the sources said.

The seller was not immediately known.