InterOil Corp. (NYSE: IOC), which agreed last month to be acquired by Australia's Oil Search Ltd., said June 30 it received an unsolicited offer from an unnamed bidder, with whom it would engage in further talks.

InterOil said Oil Search had allowed the company to proceed with the negotiations.

InterOil is an attractive takeover target for companies looking to tap the potential of Papua New Guinea's LNG reserves as it has 36.5% stake in a project in the Elk-Antelope fields.

RELATED: Oil Search Boosts LNG Push With $2.2 Billion InterOil Bid

Total SA (NYSE: TOT), Oil Search and the Papua New Guinea government are the company's partners in the project.

ExxonMobil Corp. (NYSE: XOM) is another oil and gas major with an LNG project in the country, considered a good location due to its high-quality gas and low costs.

Elk-Antelope fields could hold at least 6.2 trillion cubic feet of gas, more than enough to fill one LNG processing train.

In May, InterOil agreed to be acquired by Oil Search in a $2.2 billion deal. InterOil Chief Executive Michael Hesson had said then that the company had received a number of other proposals, but he had declined to give details.

InterOil said on June 30 that its board continued to unanimously support the Oil Search transaction. A special shareholder meeting to discuss the deal is scheduled for July 28.

InterOil shares rose 4.6% to $44 in light premarket trading.