JAKARTA- * Indonesian state energy company PT Pertamina said it will decide in June whether to continue or end negotiations with Saudi Aramco on their Cilacap oil refinery joint development, a Pertamina official said on Wednesday

* The negotiation has been extended for six months since December, but Pertamina and Aramco have not arrived on an agreement yet on the refinery's valuation, Pertamina Director Ignatius Tallulembang told reporters

* "The worst case is if we don't get anywhere (in term of agreement), the discussion will be automatically terminated," Tallulembang said. "If we don't reach agreement, both parties understand that we can't force this cooperation."

* Should the negotiation with Aramco end, Pertamina plans to start the development of the Cilacap expansion project without a partner to meet an operational target of 2025, Tallulembang said, and seek a partner during construction

* Meanwhile, Pertamina expects to select a partner for its Balikpapan refinery project in October out of currently nine candidates, Tallulembang said. The first phase of the Balikpapan project is valued at $5.3 billion

(Reporting by Wilda Asmarini Writing by Fransiska Nangoy) ((Fransiska.Nangoy@thomsonreuters.com; +62 21 2992 7610; Reuters Messaging: fransiska.nangoy.thomsonreuters.com@reuters.net))