June 18 (Reuters) - Indonesia's Pertamina has started its July procurement for 2,500 parts per million sulphur gasoil via spot tender, seeking up to 1 million barrels of the fuel, two sources with knowledge of the matter said on Tuesday.

The state-owned energy major is seeking, via its trading arm Pertamina Patra Niaga, at least two 100,000-barrel cargoes, two 200,000-barrel cargoes and one 300,000-400,000 barrel cargo for delivery, mostly within the first half of July, the sources said.

The tender closes on June 19, with offers to be valid until June 21, the sources added.

Pertamina had sought up to 6 million barrels of gasoil for June arrival, though the company is likely to have bought less than the amount it tendered for, the sources said.

Pertamina Patra Niaga did not immediately respond to a request for comment on Tuesday, which is a public holiday in Indonesia. (Reporting by Trixie Yap in Singapore and Bernadette Christina in Jakarta; Editing by Jamie Freed)