FIGHTING broke out between Thai and Cambodian forces on the border between the two countries today, killing at least nine civilians.

The nations accused each other of starting the clashes that have since led to a downgrading of diplomatic relations, with Thailand sealing all land border crossings with Cambodia.

Tensions between the south-east Asian neighbours have mounted since an armed confrontation in May that killed a Cambodian soldier. 

The Thai army said that most casualties in the recent outbreak occurred in Si Sa Ket province, where six people were killed after shots were fired at a gas station. 

At least 14 people were injured in three border provinces.

The Thai army said it launched air attacks against military targets in Cambodia, while the Cambodian Defence Ministry said the Thai jets dropped bombs on a road near the ancient Preah Vihear temple.

Clashes are continuing in at least six areas along the border, Thai Defence Ministry spokesperson Surasant Kongsiri said. 

The first, this morning, happened in an area near the ancient Ta Muen Thom temple along the border of Thailand's Surin and Cambodia's Oddar Meanchey provinces.

A livestream video from Thailand’s side showed people running from their homes and hiding in a concrete bunker as explosions sounded.

Thailand’s Ministry of Foreign Affairs said that Cambodia has attacked both military and non-military sites in Thailand, including a hospital.

“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. 

“The government is prepared to intensify our self-defence measures if Cambodia persists in its armed attack and violations upon Thailand’s sovereignty,” said Nikorndej Balankura, the ministry’s spokesman.

Cambodia’s Prime Minister Hun Manet said his country had “no choice but to respond with armed force against armed aggression.”

Earlier today, Cambodia said it was downgrading diplomatic relations with Thailand to their lowest level, expelling the Thai ambassador and recalling all Cambodian staff from its embassy in Bangkok. 

That was in response to Thailand withdrawing its ambassador and expelling the Cambodian ambassador on Wednesday in protest at a land mine blast that wounded five Thai soldiers.

The Thai embassy in Phnom Penh posted on Facebook that there were clashes at several border areas that could continue to escalate. 

The embassy urged Thai nationals in Cambodia to leave the country if they could and advised others not to travel to Cambodia unless absolutely necessary.