CIVICUS discusses the border crisis between Cambodia and Thailand with Sok Udom Deth, Professor of International Relations at Cambodia’s Paragon International University.

On 24 July, violent clashes erupted between Cambodia and Thailand. Sparked by a landmine explosion in a border area, the conflict quickly escalated into a five-day battle involving heavy artillery, drones and airstrikes. At least 43 people were killed and over 300,000 displaced. Malaysia brokered a ceasefire that took effect on 28 July, supported by US diplomatic pressure. Despite initial violations, the truce has largely held and diplomatic negotiations continue.

What triggered the border clashes and why did they escalate?

Both sides blamed the other for initiating the attacks: while observers on the Thai side suggest tensions arose from a calculated buildup by Cambodia, Cambodians tend to attribute them to hegemonic ambitions and political opportunism on the part of Thailand, along with domestic instability.

Tensions had been brewing in disputed areas along the Cambodian-Thai border since a brief clash near an area known as the Emerald Triangle that erupted on 28 May, which resulted in the death of a Cambodian soldier. Although the Cambodian government showed military restraint, it declared its intent to take the dispute to the International Court of Justice (ICJ), arguing that bilateral mechanisms over the past 25 years had been ineffective. Thailand, however, sought to resolve the dispute bilaterally.

Tensions began to escalate on the ground, particularly following the decision by Thai local armed forces to close some border checkpoints on 6 June. This prompted a series of tit-for-tat responses resulting in full border closures and import bans. The deadlock became apparent when a Joint Boundary Committee meeting in Cambodia’s capital, Phnom Penh, on 14 June resulted in only a few minor technical agreements. Making matters worse, on the same day, a Thai military commander made a statement signalling readiness to fight rather than negotiate. The Thai military has long taken a hardline approach to the border dispute, standing at odds with the civilian government and strengthening control through martial law in affected provinces.

On 15 June, Cambodia officially submitted the dispute for arbitration to the ICJ, with Thailand continuing to reiterate its non-recognition of the ICJ’s jurisdiction. The final trigger was Thailand’s accusation that Cambodia had planted new landmines that injured eight Thai soldiers. Cambodia stated that the landmines were remnants from the civil war era and the injured soldiers had deviated from their regular patrol routes, entering Cambodian territory. Following the downgrading of diplomatic ties, armed clashes erupted on 24 July.

What has been the humanitarian impact, and how has civil society responded?

The humanitarian impact has been severe. Beyond the immediate casualties – dozens of deaths and hundreds of injuries – the conflict has displaced some 300,000 people on both sides of the border. The significant military disparity – Thailand deployed F-16 and Gripen fighter jets, cluster bombs and military drones – intensified the damage. Cambodia accused Thailand of chemical smoke attacks, a claim Thailand has denied.

Education has been severely disrupted, with over 300 schools in Cambodia’s border provinces still closed as of early August. Economic life in border areas has also ground to a halt. There has been an exodus of workers, with over 750,000 Cambodian migrant workers fleeing Thailand, causing disruption to its agricultural and construction industries.

Cambodian migrant workers have suffered abuse from ultranationalist groups in Thailand who physically attacked them, accusing them of being ‘troublemakers’ and ‘spies’, and of ‘stealing jobs’ from Thai people. This caused fear to spread among the Cambodian community in Thailand.

Civil society has responded with remarkable speed and compassion. In Cambodia, local civil society organisations, volunteer groups, private firms and influencers organised donation drives, volunteer help and psychosocial support for displaced people. Artists and community groups staged comedy performances to lift morale. Similar humanitarian efforts have been seen on the Thai side.

What role did Malaysia and the USA play in mediating the dispute?

Early mediation efforts faced significant challenges. In the initial days of the conflict, Malaysian Prime Minister Anwar Ibrahim, current Chair of the Association of Southeast Asian Nations (ASEAN), offered mediation support, but achieved limited success. As the violence intensified, Cambodia called for a ceasefire and urged the United Nations Security Council, ASEAN and the international community to mediate. This appeal reflected Cambodia’s perception of its greater social, economic and military vulnerability.

The breakthrough came five days into the fighting, when both sides agreed to ceasefire negotiations in the Malaysian capital, Kuala Lumpur, with Malaysia presiding and US representatives cochairing talks. Crucially, prior to the negotiations, the leaders of Cambodia and Thailand had a phone call with Donald Trump, who urged them to reach a peace deal and linked it to favourable US tariff rates. This economic incentive proved effective, and following the ceasefire, the USA granted reduced tariffs of 19 per cent to both countries. Trump also rewarded the mediator, reducing tariffs on Malaysia.

How’s the ceasefire holding?

Several incidents have tested the agreement. Thailand currently holds 18 Cambodian soldiers as detainees. The Thai military accuses them of encroaching on Thai territory, while Cambodia claims they were tricked and captured by Thai forces after the ceasefire.

But recent diplomatic efforts have brought encouraging news. A General Border Committee meeting on 7 August reinforced the ceasefire agreements through specific commitments. Both sides agreed to avoid unprovoked firing, maintain current troop deployments without further repositioning, refrain from increasing forces along the border, not construct or enhance military infrastructure beyond their borders, abstain from using any forces against civilians or civilian objects under all circumstances, comply with international humanitarian law in treating captured soldiers and refrain from spreading disinformation.

While the ceasefire remains in effect, it’s too early to fully assess its durability, particularly given the evolving domestic political situation in Thailand and uncertainty about the Thai military’s next moves.

What steps are needed to prevent future clashes and resolve the dispute?

Sustainable peace will require honest political will from both countries to pursue solutions in the short and long term. In the short term, the priority is to consolidate the ceasefire through an independent ASEAN-supported observation mechanism and immediately reopen key border checkpoints to allow humanitarian aid and essential cross-border trade to resume. Equally important, practical incident-management procedures must be agreed and publicly communicated so small incidents do not spark escalation.

In the long-term, both governments should commit to submitting remaining territorial disagreements to impartial legal arbitration such as through the ICJ and to accept its rulings. In parallel, informal diplomatic channels involving civil society groups and former officials as a complementary approach to diplomacy, plus sustained people-to-people exchanges, will be needed to rebuild trust. Only a combination of measures to build trust and prevent incidents, legal resolution and societal healing can break the cycle of periodic violence and deliver lasting stability along the border.

The opinions expressed in this interview are those of the interviewee and do not necessarily reflect the views of CIVICUS.