Thai troops detained 18 Cambodian soldiers who surrendered during a border clash, despite a ceasefire being agreed.

The Royal Thai Army captured the Cambodian forces after the Thai military conducted a 'counter-operation' in Sisaket, Thailand, on July 29.

Major General Vinthai Suwaree, spokesman for the Thai army, said Thai soldiers retaliated when the Cambodians reportedly fired heavy and curved trajectory weapons, allegedly violating a truce agreed upon on Tuesday with the help of US President Donald Trump.

The Thai government's public relations department said in a statement: 'MFA (Ministry of Foreign Affairs) Thailand informed that, following the border clash, 18 surrendering Cambodian soldiers have been disarmed, detained and treated with appropriate care in accordance to international law and human rights principles by the Thai Army, and subject to further relevant processes.'

The 18 detained soldiers included one sub-lieutenant, two sergeant majors second class, 12 sergeants, two corporals, and one private first class.

Among them was Sergeant Mom Ridthi, who was taken to a hospital to undergo surgery for hip and arm injuries.

The prisoners of war were being held at a secure facility under the Second Army Region, where Thai officials said they were given clothing, food, drinking water, and medical treatment according to international law and human rights principles.

Thailand earlier accused Cambodia of allegedly violating a ceasefire, saying Thai troops in Sisaket 'came under attack by small arms fire and grenade assaults launched by Cambodian forces'.

Thai government spokesman Jirayu Huangsab later said in a statement that Thailand 'maintained control of the situation', adding general border conditions were 'normal' on Wednesday.

The escalating military confrontation - the bloodiest in more than a decade - flared in long-disputed border areas as Thailand and Cambodia accused each other of instigating the violence on July 24.

The Thai army claimed the clash began when six armed Cambodian soldiers approached a Thai outpost after a drone was heard near a disputed Khmer temple. Thai troops said they shouted warnings and claimed the Cambodians opened fire first.

However, Cambodia's Defense Ministry accused Thailand of provoking the violence, saying its forces acted in self-defense.

Officials said at least 43 people have been killed and more than 300,000 displaced on both sides of the border.

Both sides have reached a truce midnight on Monday, following talks facilitated by Malaysian Prime Minister Anwar Ibrahim, chair of the Association of Southeast Asian Nations (ASEAN).

He said: 'This is a vital first step toward de-escalation and the restoration of peace and security.'

President Trump had earlier threatened to pause trade deals with both countries if clashes continued.

He said after the ceasefire was forged: 'By ending this War, we have saved thousands of lives ... I have now ended many Wars in just six months — I am proud to be the President of PEACE!'