First came a push from the Malaysian premier, then China reached out, but it was only after U.S. President Donald Trump called Thailand’s leader last week that Bangkok agreed to talks with Cambodia to end an escalating military conflict.A flurry of diplomatic efforts over a 20-hour window sealed Thailand’s participation in ceasefire negotiations with Cambodia, hosted in Malaysia, halting the heaviest fighting between two Southeast Asian countries in over a decade.Reuters interviewed four people on both sides of the border to piece together the most detailed account of how the truce was achieved, including previously unreported Thai conditions for joining the talks and the extent of Chinese involvement in the process.When Trump called Thai Acting Prime Minister Phumtham Wechayachai on Saturday, two days after fighting erupted along a 200-km-long stretch of the border, Bangkok had not responded to mediation offers from Malaysia and China, said a Thai government source with direct knowledge.“We told him that we want bilateral talks first before declaring a ceasefire,” the source said, asking not to be named because of the sensitivity of the issue.Thailand had already made it clear that it favoured bilateral negotiation and initially did not want third-party mediation to resolve the conflict.On Sunday, a day after his initial call, Trump said that Thailand and Cambodia had agreed to meet to work out a ceasefire, and that Washington wouldn’t move ahead with tariff negotiations with both until the conflict had ended.The source said as the Thai and Cambodian foreign ministries started talking, following Trump’s call, Bangkok set out its terms: the meeting must be between the two prime ministers and at a neutral location.“We proposed Malaysia because we want this to be a regional matter,” the source said.“The U.S. really pushed for the meeting,” a second Thai source said, “We want a peaceful solution to the conflict so we had to show good faith and accept.”A Thai government spokesperson did not immediately respond to questions from Reuters.Cambodia had accepted the initial Malaysian offer for talks but it was Thailand that did not move ahead until Trump’s intervention, said Lim Menghour, a Cambodian government official working on foreign policy.Prime Minister Hun Manet’s government also kept a channel open with China, which had shown interest in joining any peace talks between the neighbours, he said, reflecting Phnom Penh’s close ties to Beijing. “We exchanged regular communication,” Lim Menghour said.GOOD FAITHOn Monday, Phumtham and Hun Manet went to the Malaysian administrative capital of Putrajaya, where they were hosted by Prime Minister Anwar Ibrahim, also the current chair of the 10-member Association of Southeast Asian Nations regional bloc.At the end of their talks, the two leaders stood on either side of Anwar, who read out a joint statement that said Thailand and Cambodia would enter into a ceasefire from midnight and continue dialogue.The rapid parleys echoed efforts to diffuse severe border clashes between Thailand and Cambodia in 2011, which took several months including mediation efforts by Indonesia, then chair of ASEAN.But those talks had not directly involved the U.S. and China. The fragile ceasefire was holding as of Thursday, despite distrust on both sides, and neither military has scaled down troop deployment along the frontier.Thailand and Cambodia have, for decades, quarrelled over undemarcated parts of their 817 km (508 miles) land border, which was first mapped by France in 1907 when the latter was its colony.In recent months, tensions began building between the neighbours after the death of a Cambodian soldiers in a skirmish in May and escalated into both militaries bolstering border deployments, alongside a full-blown diplomatic crisis.After a second Thai soldier lost a limb last week to a landmine that Thailand alleged Cambodian troops had planted, Bangkok recalled its ambassador to Phnom Penh and expelled Cambodia’s envoy. Cambodia has denied the charge. The fighting began soon after.Since the ceasefire deal, Hun Manet and Phumtham have been effusive in their praise for Trump, who had threatened 36% tariffs on goods from both countries coming to the U.S., their biggest export market.The Thai sources did not say whether tariff talks had been impacted by the border clashes. Lim Menghour said after the “positive talks, President Donald Trump also showed positive developments” regarding tariffs, without elaborating.Trump said tariff negotiations with both countries resumed after the ceasefire agreement. U.S. Commerce Secretary Howard Lutnick said on Wednesday that Washington has made trade deals with Cambodia and Thailand, but they are yet to be announced.