BANGKOK — At least 12 have been killed since border clashes broke out between Thailand and Cambodia on Thursday morning, the Thai authorities have said.

Both countries accused the other of shooting first in a serious escalation of their long-running border dispute.

The Thai army first reported a death toll of nine civilians, stating six citizens had died in Sisaket province, two in Surin province and one in Ubon Ratchathani province. At least 17 other people have been wounded, according to Thai authorities.

Cambodia, which is yet to release its own casualty figures, claimed that Thai jets dropped bombs on a road near the ancient Preah Vihear temple.

The fighting began on Thursday morning close to the ancient Ta Muen Thom temple, beside the border between Thailand’s Surin province and Cambodia’s Oddar Meanchey province.

It comes after months of heightened tensions between the neighbours, following the death of a Cambodian soldier in a border skirmish in May.

The Thai army said six armed Cambodian soldiers opened fire near one of its military stations on Thursday, while Cambodia blamed Thailand for causing the latest clashes.

In a statement published on Thursday, Cambodia's foreign ministry said it “condemns in the strongest possible terms this reckless and hostile act by Thailand”, urging its neighbour to cease hostilities.

Thailand’s foreign ministry also issued a similar message, in which it encouraged Cambodia to bring the flare-up to an end.

“The Royal Thai Government calls upon Cambodia to take responsibility for the incidents that have occurred, cease attacks against civilian and military targets, and stop all actions that violate Thailand’s sovereignty,” it said.

Both Cambodia and Thailand have downgraded diplomatic relations since Wednesday, with Cambodia recalling its diplomatic staff and expelling the Thai ambassador on Thursday.

Thailand also sealed all land border crossings with Cambodia, following a land mine blast on Wednesday that injured five Thai soldiers, one of whom lost a leg.

Thai authorities claim that Cambodian troops have recently laid mines in previously safe areas, something Cambodia strongly rejects, saying that they are the legacy of old wars and unrest.

The border dispute between the two countries started more than a century ago, following the end of France’s occupation of Cambodia. — BBC