Thai marines dismantled a Cambodian improvised explosive device that was seized from a home in disputed territory.

Footage shows a Thai officer disassembling and defusing a bomb fitted with C4 explosives in the recently captured Ban Nong Ri area of Trat province on December 19.

Rear Admiral Paraj Ratanajaipan, Royal Thai Navy spokesman, said the bomb was found during clearing operations in the contested strip of land near the border, where a cache of anti-personnel landmines was also discovered.

The use of landmines by Cambodia would be a breach of the Ottawa Treaty banning the devices.

The military chief said: 'Such conduct constitutes a serious breach of the fundamental principles of international humanitarian law, including obligations under conventions prohibiting the use of anti-personnel landmines.

‘Furthermore, the discovered evidence represents only a portion of the explosive hazards that mine clearance teams have been able to detect and neutralise. It is assessed that a significant number of such devices may still remain buried in the area.

‘The Royal Thai Navy affirms that these actions are wholly unacceptable within the international community and calls upon the Cambodian side to assume responsibility for its conduct and to immediately cease any actions that endanger the lives of military personnel and innocent civilians.

‘The Royal Thai Navy will continue mine clearance and explosive ordnance disposal operations in the area to ensure the highest level of safety for both personnel and the public, and reserves the right to pursue further actions in accordance with applicable legal frameworks and relevant international mechanisms.'

The Thai Navy said soldiers recovered training documents for the use of landmines, allegedly proving that Cambodia had violated the Ottawa and Geneva Conventions. The international humanitarian laws ban the use of landmines, which can kill or maim civilians for years even after conflicts end.

Cambodia and Laos are two of the countries with the highest number of mines and unexploded ordnance, most of which was dropped by the United States during the American-Vietnam War.

The BBC has previously reported that Thailand has provided 'compelling evidence' that Cambodia has also 'laid new landmines in bad faith' that have continued to injure Thai soldiers along the border, in what would be a breach of the Ottawa Treaty.

Territorial clashes flared up earlier this year before a brief ceasefire, but started again this month when Cambodian troops are said to have fired on a Thai engineering team building an access road in a disputed border area.

In the most recent battles, at least 21 Thai soldiers and one civilian have been killed.

In Cambodia, the number of military fatalities is believed to be much higher, though regime chiefs have not revealed the actual figure.

Around 600,000 people have been displaced on both sides of the border.

Cambodia's assault has largely been wayward, unguided rockets fired indiscriminately into Thai territory, including an attack on July 24 that killed eight people and injured 13 others. Thailand has used precision drone strikes and fighter jet strikes on military sites.

Former Khmer Rouge henchman and Cambodian dictator Hun Sen - who was a leading figure in the genocide of his own people in the 1970s before assuming power in 1985 and overseeing the murder of thousands of opposition figures and critics - has repeatedly claimed that he wants peace and that Thailand is the aggressor.

Thai officials claim the ongoing border confrontations are a threat to national security, and the areas must be secured.