Footage shows soldiers patrolling the Royal Embassy of Cambodia in Bangkok today following the expulsion of diplomats due to the ongoing border clashes.

Officials said at least 14 civilians were killed by rockets fired from the neighbouring country in Surin and Si Sa Ket provinces on Thursday.

The escalating military confrontation - the bloodiest in more than a decade - flared in long-disputed border areas as both sides accused each other of instigating the violence.

Thai Health Minister Somsak Thepsuthin said at least 15 people, including a soldier and two children Bandit Aunjit and Namkhong Boontang aged seven and eight, were killed in the crossfire, while some 32 were injured.

A provincial officer in Cambodia's Oddar Meanchey province confirmed one person was wounded and five killed in Thai attacks.

More than 120,000 residents on both sides of the border have fled as the fighting continued to rage today.

The Royal Thai Army reported that Thai military officers at Prasat Ta Muen temple in Surin heard the sound of an unmanned aerial vehicle at 7:35 am but could not pinpoint its location.

Six armed Cambodian soldiers, including one with an RPG, then approached the barbed wire area in front of the Thai base, prompting Thai soldiers to shout at them to stop.

At 8:20 am, the Cambodian side reportedly fired in the opposite direction of the base to the east of the castle before artillery fire was launched around 9 am.

Jirayu Huangsap, spokesman for the Prime Minister's Office, said the government received military information and 'clear evidence' that the Cambodian side initiated the attack.

However, Cambodian PM Hun Manet said Thailand initiated the attack, forcing him to retaliate.