Phnom Penh: H.E Hun Sen, Cambodia’s Acting Head of State, has reaffirmed Cambodia’s position to pursue international legal mechanisms under the 1982 United Nations Convention on the Law of the Sea (UNCLOS), while rejecting the establishment of any new bilateral negotiation framework with Thailand following Thailand’s unilateral cancellation of the 2001 Memorandum of Understanding (MOU 2001).

In a message posted on his official Facebook page on May 12, 2026, Hun Sen reminded the Cambodian government to maintain a clear and consistent stance regarding the maritime dispute with Thailand and continue moving directly toward international legal mechanisms.

The Acting Head of State referred to Thai media reports published on May 11, 2026, which quoted Thailand’s foreign minister as saying that after the cancellation of the 2001 MOU, both countries should proceed under the framework of UNCLOS, and that “the primary method should first be bilateral negotiations between the two parties.”

Hun Sen stated that if the remarks were accurately reported, Thailand’s call for new bilateral negotiations directly contradicts its own actions in unilaterally revoking the 2001 MOU, which had previously served as the bilateral framework for negotiations over overlapping maritime claims.

He stated: “The phrase ‘the primary method should first be bilateral negotiations between the two parties’ clearly contradicts Thailand’s actions in unilaterally canceling the 2001 MOU, which already eliminated the bilateral negotiation framework for the overlapping maritime area.”

The Acting Head of State also recalled that on May 6, 2026, he had already warned against creating any new bilateral mechanism to replace the previous framework that Thailand itself had terminated.

“We regret Thailand’s cancellation of the 2001 MOU, but we also thank Thailand for helping Cambodia move toward international mechanisms instead,” Hun Sen added.

According to a report published by The Star on May 12, 2026, Sihasak Phuangketkeow, Thailand’s Deputy Prime Minister and Foreign Minister, stated that Thailand “does not recognize” Cambodia’s use of the 2001 Memorandum of Understanding (MoU 44) as a registered document related to maritime boundary issues.

Speaking at Government House in Bangkok, Sihasak said Cambodia and Thailand should discuss overlapping maritime claims “only under the framework of the United Nations Convention on the Law of the Sea (UNCLOS).”

He emphasized that both Cambodia and Thailand are parties to the 1982 UNCLOS Convention, which provides internationally recognized legal principles for resolving maritime disputes and guiding future negotiations.

“As for MoU 44, we have already canceled it,” Sihasak stated. He further noted that negotiations under UNCLOS could help create a more constructive process and avoid unnecessary delays, although he acknowledged that the two sides have not yet agreed on which specific mechanism would ultimately be used.

In the same interview, Sihasak also rejected claims that Cambodia had registered MoU 44 as evidence related to maritime boundary lines that could affect Thailand’s Koh Kut Island.

He argued that such claims “cannot stand under UNCLOS” because maritime boundary issues must be assessed according to international law and universally accepted legal provisions.

Sihasak added that he did not know what documents Cambodia had submitted or through which procedures, but confirmed that both Thailand and Cambodia would continue discussions under the UNCLOS framework.

The latest developments come after the Thai government officially revoked the 2001 MOU on May 5, 2026, ending the bilateral framework that had governed negotiations over overlapping maritime zones and oil and gas resources in the Gulf of Thailand.

At the same time, Cambodia has been actively promoting the use of “Compulsory Conciliation” mechanisms under UNCLOS, while Thailand continues to prioritize bilateral negotiations.

Political observers say Hun Sen’s latest statement sends a clear political message that Cambodia no longer intends to return to a new bilateral negotiation framework after Thailand’s unilateral withdrawal from the 2001 agreement, and instead will rely on international legal mechanisms to safeguard its maritime rights and national interests.