Clashes between Thai and Cambodian troops continued throughout the night and into Friday morning after a massive escalation of tensions.
On Thursday, Thailand's military said it carried out airstrikes on the Cambodian side of the border after it said the Cambodian army launched artillery shells over the Thai border.
The clash began in the morning near the contested Ta Moan Thom Temple. Both sides said the other started the shooting.
As of Friday afternoon, Thailand's acting Prime Minister Phumtham Wechayachai said that he knew of "more than 20 deaths," as well as dozens of injuries.
It is believed that most of these casualties are Thai civilians. Cambodian officials have not yet released any official figures on casualties.
Since May, tensions have escalated between the Southeast Asian neighbors after a Cambodian solider was killed in an exchange of fire with Thai troops while digging trenches on the disputed frontier.
Earlier this week, a landmine injured several Thai soldiers, and Bangkok immediately accused Cambodia of laying new landmines, while Phnom Penh argued that it was most likely one of many mines laid in the area in the 1980s.
Thailand withdrew its ambassador from Phnom Penh and sent home Cambodia's envoy. Cambodia followed suit, and both sides downgraded diplomatic relations on July 23, a day before the latest clashes broke out.
Whether the military strikes will continue and escalate into a wider war remains to be seen.
"The armed conflict could be resolved very quickly; war is not remotely inevitable," Bradley Murg, senior research fellow at the Cambodia Institute for Cooperation and Peace, told DW.
"However, the underlying tensions and resolution of the border issue will be deeply protracted," he added.
Long-simmering tensions boil over
Cambodia and Thailand have both claimed sovereignty over several patches of territory for more than a century, following the French colonial authorities' redrawing of national borders in French Indochina.
While both sides have attempted to resolve these issues through negotiation, military clashes broke out in 2008 over ownership of a temple near the town of Preah Vihear.
The tensions lasted for five years, spiking in 2011 when several troops were killed in a skirmish. In 2013, the International Court of Justice ruled most of the territory in question belonged to Cambodia.
The latest violence is the worst since 2011, and involves slightly different dimensions involving nationalist sentiment and internal Thai politics.
In 2024, segments of the Thai and Cambodian public began to raise the issue of Koh Kood, an island officially part of Thailand but claimed by Cambodia. These revanchist claims then spread to several other border areas.
After the Cambodian solider was killed digging trenches in May, both countries dispatched troops to the region and tightened border controls.
A phone call in June between Cambodian Senate president Hun Sen and Thai Prime Minister Paetongtarn Shinawatra was an attempt to ease tensions, but ended up escalating matters further.
Hun Sen, for decades Cambodia's strongman prime minister, and still the de facto leader, leaked the phone call, during which Paetongtarn called him her "uncle" and made disparaging comments about the Thai military.
Border crisis gets political
These comments sparked a crisis within Thai politics, with a major party leaving the Paetongtarn coalition government. Eventually, the Constitutional Court intervened to suspend her for her actions.
Joshua Kurlantzick, senior fellow for Southeast Asia at the Council on Foreign Relations, told DW that this conflict potentially "further boosts the power of the Thai army and gives them more influence over politics."
Cambodian Prime Minister Hun Manet, Hun Sen's son, said on Thursday that "Cambodia has always adhered to resolving issues peacefully, but in this case, we have no choice but to respond with force against this armed invasion."
A diplomatic source in Phnom Penh, who requested anonymity, told DW that the conflict poses the most significant challenge to Hun Manet since he assumed the role of prime minister from his father in 2023. If things go badly for Cambodia, the relatively inexperienced leader could take most of the blame.
"The current flare-up between the two sides that has escalated into a military clash involving heavy weaponry may get worse before it can ease," Thitinan Pongsudhirak, a senior fellow at Thailand's Institute of Security and International Studies, a think tank, told DW.
"The danger is that the Thai army has taken charge of border policy, while Hun Sen appears intent on further provoking and agitating a weak and divided Thai government with Prime Minister Paetongtarn Shinawatra under suspension for her compromising phone call with him, which was secretly recorded," he added.
How could the latest conflict play out?
Zachary Abuza, a professor at the National War College in Washington, noted that a prolonged military conflict does not favor Cambodia.
The terrain in the "Emerald Triangle" region favors Thailand, and the Thai military is a better-equipped force, Abuza told DW.
A clear example of this came on Thursday morning, when Cambodia launched indiscriminate rocket and artillery strikes that seemingly hit only civilian targets. In comparison, Thailand has launched far more surgical air strikes.
Thailand also has the upper hand because it has more ways to economically hurt Cambodia, Abuza added.
"Thailand has more ways to punish Cambodia. Cambodia is far more dependent on exports to Thailand than the other way around. While Thailand needs Cambodian workers, Cambodia needs remittances more, and there are plenty of workers from Burma and Laos," he said.
Moreover, Thailand can play a significant role in putting international pressure on Cambodia's illegal cyber scam industry.
"Bangkok understands that this is the center of gravity for Hun Manet; it's these proceeds that allow him to maintain the Cambodian People's Party's (CPP) patronage network," Abuza said.
As the current round of violence escalates, 100,000 people have fled border regions. The United Nations Security Council is due to hold an emergency meeting later Friday.
Malaysia, the current chair of the Association of Southeast Asian Nations (ASEAN) bloc, has spoken with Cambodian Prime Minister Hun Manet and the Thai acting Prime Minister, Phumtham.
"In our conversations, in Malaysia's capacity as ASEAN Chair for 2025, I appealed directly to both leaders for an immediate ceasefire to prevent further hostilities and to create space for peaceful dialogue and diplomatic resolution," Anwar said in a statement.
Political scientist Thitinan said one offramp for the conflict could be third-party mediation, by either ASEAN or the UN.
However, amid the acute violence, getting both sides to climb down with dialogue is a tough task.
"The UN, the US or even China does not seem to have sufficient trust on both sides to facilitate a diplomatic way out," Thitinan said.
"The military situation can worsen before any dialogue and compromise takes hold because both sides are driven by nationalist sentiments and cannot be seen to budge."
