Thai police fired tear gas and rubber bullets at Cambodian civilians in a disputed border area on Wednesday, authorities in both countries said, the most significant escalation since they declared a ceasefire to end a deadly five-day conflict in July.
At least 23 Cambodians were injured in the incident, according to Cambodian authorities, while Thailand's military said an unspecified number of Thai officials had also sustained injuries.
The clash took place at a disputed frontier settlement, which Thailand says is part of its Ban Nong Ya Kaew village in Sa Kaeo province, but Cambodia says is part of Prey Chan village in Bantheay Meanchey province.
Read: Thailand, Cambodia approve ceasefire
Thai authorities erected barbed wire fences in the area last month and for weeks there have been protests by civilians from both sides of the border.
Thailand and Cambodia have for more than a century contested sovereignty at various undemarcated points along their 817 km (508 miles) land border, which was first mapped by France in 1907 when Cambodia was its colony.
Tensions over disputed areas spiraled into a border conflict in July, when the fiercest fighting between the neighbours in decades killed at least 48 people and temporarily displaced hundreds of thousands.
Read more: Thailand estimates $300m loss from Cambodia border clash
The fighting ended after both countries agreed a ceasefire brokered in Malaysia on July 28, and the border has largely remained calm since.
On Wednesday, Cambodia's information minister Neth Pheaktra accused Thai officials of encroaching across the border, and said they used "tear gas, rubber bullets and noise-making devices against Cambodian civilians."
Cambodian Prime Minister Hun Manet has sent out letters to world leaders, seeking support from the international community and the regional bloc ASEAN to stop what he described as Thailand's "unilateral actions that risk escalating tensions and widening the conflict", a Cambodia government statement said.
Also read: Thailand, Cambodia clashes intensify
The Thai army said in a statement that Thailand's use of force was a response to provocation from some 200 Cambodian protesters, some of whom dismantled Thai defensive barriers, threw sticks and stones and fired slingshots at Thai officials, causing injuries.
The actions of the riot police were aimed at preventing the situation from escalating into civil disorder, it added.
The US government said it was aware of the situation and urged the governments of both Cambodia and Thailand to de-escalate tensions.
A US State Department spokesman called on the two sides to quickly finalise the "terms of reference" to establish a longer-term observer mission comprised of ASEAN member states on both sides of the border.
COMMENTS
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ