Eleven civilians killed as Thailand and Cambodia exchange fire in escalating border dispute

Among those killed was an eight-year-old boy, the army said in a statement.

It said most casualties occurred in Si Sa Ket province, where six people were killed after shots were fired at a fuel station.

Another 14 people have been injured in three Thai border provinces.

Thailand's health minister Somsak Thepsuthin confirmed the fatalities to reporters, adding Cambodia's actions, including an attack on a hospital, should be considered war crimes.

Both countries accuse one another of starting the military clashes and have downgraded their diplomatic relations in the rapidly escalating dispute. Thailand has also sealed all land border crossings with Cambodia.

Early on Thursday, a Thai F-16 fighter jet bombed targets in Cambodia, according to Thailand's army.

"We have used air power against military targets as planned," Thai army deputy spokesperson Richa Suksuwanon said.

Cambodia's defence ministry said Thai jets had dropped bombs on a road near the ancient Preah Vihear temple, saying it "strongly condemns the reckless and brutal military aggression of the Kingdom of Thailand against the sovereignty and territorial integrity of Cambodia".

Clashes are ongoing in at least six areas along the border, the Thai defence ministry said.

Thailand's foreign ministry said Cambodian troops fired "heavy artillery" on a Thai military base on Thursday morning and also targeted civilian areas, including a hospital.

"The Royal Thai Government is prepared to intensify our self-defence measures if Cambodia persists in its armed attack and violations upon Thailand's sovereignty," the ministry said in a statement.

A livestream video from Thailand's side showed people, including children and the elderly, running from their homes and hiding in a concrete bunker as explosions sounded.

The clash happened in an area where the ancient Prasat Ta Muen Thom temple stands along the border of Thailand's Surin province and Cambodia's Oddar Meanchey province.

Earlier on Thursday, Cambodia downgraded diplomatic relations with Thailand to their lowest level, expelled the Thai ambassador and recalled all Cambodian staff from its embassy in Bangkok.

The day before, its neighbour withdrew its ambassador and expelled the top Cambodian diplomat in protest after five Thai soldiers were wounded in a land mine blast, one of whom lost part of a leg.

A week earlier, a land mine in a different contested area exploded and wounded three Thai soldiers, including one who lost a foot.

Relations between the southeast Asian neighbours have collapsed after a Cambodian soldier was killed in an armed confrontation in a disputed border area in May.

Nationalist passions on both sides have further inflamed the situation, and Thailand's prime minister was suspended earlier this month as an investigation was opened into possible ethics violations over her handling of the border dispute.

Border disputes are longstanding issues that have caused periodic tensions between the countries. The most prominent and violent conflicts have been around the 1,000-year-old Preah Vihear temple.

In 1962, the International Court of Justice recognised Cambodian sovereignty over the temple area.

-SKY NEWS