Chinese PHL-03 Rocket Spurs Fresh Thailand–Cambodia Clash as Bangkok Strikes Pre-emptively

Tensions along the Thailand–Cambodia frontier flared after Cambodia moved a Chinese-made PHL-03 multiple-launch rocket system (MLRS) closer to the disputed border, prompting Thailand to launch pre-emptive air strikes on military depots. The PHL-03’s roughly 81-mile range raised concerns that airfields, hospitals and other deep targets in Thailand could be vulnerable if the system were deployed.

What Happened

Bangkok says it struck facilities after intelligence indicated attempts to "lock on the co-ordinates" of Thai infrastructure. Thai defence ministry spokesman Rear-Adml Surasant Kongsiri told Reuters the strikes were aimed at degrading Cambodia’s ability to target civilian and military sites and that they had been successful.

"Based on our intelligence as well, there have been attempts to lock on the co-ordinates of these facilities," Rear-Adml Surasant Kongsiri said.

Why the PHL-03 Matters

The Chinese PHL-03 fires large-calibre 300mm rockets to a maximum range of about 81 miles (approximately 130 km), far beyond the reach of older BM-21 systems Cambodia previously used. The International Institute for Strategic Studies estimates Cambodia’s armed forces possess six PHL-03 launchers, making the system the heaviest and longest-range artillery in Phnom Penh’s inventory.

Evacuees have taken refuge in Oddar Meanchey province - Heng Sinith/AP Photo

Anthony Davis, a Bangkok-based security analyst, described the system’s significance: "You’re talking large-calibre, 300mm munitions, that can be delivered up to a range of 81 miles … so able to reach targets deep inside Thai territory." The prospect of such strikes prompted Thai officials to act pre-emptively to limit the perceived threat.

Supply Lines and Regional Dynamics

Thai intelligence documents cited by The New York Times reported that in June Chinese Y-20 transport aircraft made multiple flights to Cambodia carrying rockets, artillery shells and mortars loaded into 42 containers. Human rights groups later concluded that most of the rockets used by Cambodia in earlier strikes originated from China.

China has become Cambodia’s largest military supplier since the United States curtailed arms sales to Phnom Penh in 2010. Beijing’s support includes weapons deliveries and major infrastructure projects, notably upgrades at the Ream Naval Base, which have alarmed neighbours that fear expanded Chinese military access in the Gulf of Thailand.

Locations of military clashes along the disputed border between Thailand and Cambodia via Reuters

China’s Position

Analysts stress that supplying arms does not necessarily mean Beijing wants an escalation. Dr Rahman Yaacob of the Australian National University said Chinese officials reportedly asked Cambodia not to fire the PHL-03 in July, fearing that use of the system would dangerously escalate the conflict.

Human Cost and Political Drivers

Violence in late July left 48 people dead and displaced some 300,000 during a five-day stand-off reportedly triggered by competing interpretations of a colonial-era map. Since the latest breach of the fragile ceasefire, at least 10 people have been killed, nearly two dozen wounded and hundreds of thousands evacuated as new clashes unfold. Observers say domestic politics and rising nationalist sentiment in both capitals have hardened rhetoric and limited room for compromise.

Gen Chaiyapruek Duangprapat, the Thai army chief of staff, has warned of efforts to degrade Cambodia’s military capability — an approach analysts interpret as a signal from Bangkok that it can and will target advanced systems such as the PHL-03 if necessary.

Army Region 2 via Facebook/Handout via Reuters

Arms Trade Context

While China has supplied Cambodia with advanced rockets, it has also sold arms to Thailand: Stockholm International Peace Research Institute data show Thailand spent nearly £375 million on Chinese weaponry between 2019 and 2023, compared with just over £75 million from the United States during the same period. This dual relationship complicates Beijing’s ability to manage the dispute without appearing to favour one side.

Outlook: The presence of long-range Chinese-made systems on a contested frontier increases the risk of miscalculation. Analysts warn that, unless diplomatic pressure or confidence-building measures are quickly restored, the conflict could escalate further with significant humanitarian consequences.

Sources: Reporting by Reuters, The New York Times and The Telegraph; analysis from IISS, SIPRI and regional security experts.