Thai protesters rallied at the Cambodian embassy after a soldier lost his leg in a landmine explosion at the border.

The nationalists converged on the embassy in Bangkok on Sunday, waving Thai flags and blasting speeches on a sound truck as they decried what they falsely claimed were newly planted explosives.

Cambodia still has up to six million unexploded devices that were dropped by the United States. It was Thailand that provided the United States with military bases throughout the 1960s and 1970s for campaigns that resulted in the widespread presence of unexploded ordnance, including mines.

Protest leader Phichit Chaimongkol incorrectly blamed Cambodia for planting new mines.

He said: ‘Today, everyone is here to symbolically express a message to the Cambodian government and military regarding their conduct, which encroached upon our sovereignty by planting hundreds of landmines on Thai territory.

‘This shows that Cambodia has shown great contempt for Thailand and views Thailand as an enemy, which constitutes a severe threat to Thailand's national security.

‘Furthermore, Cambodia has also violated the Ottawa Treaty, which stipulates: 'Prohibiting the Use, Stockpiling, Production and Transfer of Anti-Personnel Mines and on their Destruction.''

Three Thai soldiers were injured, with one of them losing his leg, after landmines exploded during their patrol of the Chong Bok border area in Ubon Ratchathani on July 16.

Thailand's Ministry of Foreign Affairs said in a statement: 'The Royal Thai Government condemns in the strongest terms the use of anti-personnel mines. Such an act is a clear violation of the sovereignty and territorial integrity of the Kingdom of Thailand, which is an outright breach of the principles that are fundamental to international law and enshrined in the United Nations Charter, as well as a clear violation of the obligations under the Anti-Personnel Mine Ban Convention.'

Thai authorities said they will seek recourse through bilateral channels, and urged Cambodia to 'cooperate on humanitarian demining efforts along the border of the two countries as bilaterally agreed by both Prime Ministers'.

Tensions between Thailand and Cambodia escalated after a clash between troops from both countries in a disputed area in Nam Yuen district, Ubon Ratchathani, on May 28, resulting in the death of a Cambodian sergeant.

Thailand expressed its intention to resolve the dispute through existing bilateral mechanisms. However, Cambodia vowed to take the case before the International Court of Justice in The Hague.

Thailand and Cambodia have a fractious history. The Khmer Empire, a precursor to modern-day Cambodia, once stretched across much of Southeast Asia before the ancient leaders moved their base south to Phnom Penh in the 16th century amid water shortages. The abandoned land was then taken over by the Siamese kingdom.