Thailand and Cambodia agreed on February 22 to accept Indonesian observers and avoid further clashes over a border dispute that has claimed at least 10 lives and displaced thousands, officials said.
The agreement came during a meeting of foreign ministers from the Association of Southeast Asian Nations (ASEAN) in Indonesia, which holds the current chair of the 10-member block.
Indonesian Foreign Minister Marty Natalegawa, speaking on behalf of ASEAN, said it was a "unique arrangement" for a grouping that devotes most of its time to trade and avoids conflict resolution.
"Indonesia will observe on both sides of the border... This is an observer team, not a peace-keeping or peace-enforcement team. The observer team will be unarmed," he told reporters after the talks.
He said Cambodia and Thailand had also requested Indonesia's "engagement" in subsequent bilateral negotiations, the first of which would be convened in Indonesia at a date to be specified.
"With hard work we can make things happen," the minister added, referring to weeks of behind-the-scenes activity by his office and the Jakarta-based ASEAN secretariat, headed by former Thai foreign minister Surin Pitsuwan.
Thailand and Cambodia have each accused the other of starting the clashes, which erupted around the Hindu temple of Preah Vihear earlier this month.
The temple belongs to Cambodia but the surrounding area is claimed by both sides.
Thailand has resisted Cambodian calls for third-party mediation but now appears ready to allow Indonesia, as the chair of ASEAN, to play a formal role as observer of the ceasefire and future bilateral talks.
Speaking earlier in Phnom Penh, Cambodian Prime Minister Hun Sen said a third party was essential as Thailand "signs documents with hands, but cancels them by feet".