Second Army Region Commander Lt Gen Boonsin Padklang has advised Prime Minister Paetongtarn Shinawatra to "be mindful" and support the national interest with a moral policy when handling the border dispute with Cambodia.
He also said he suggested the prime minister set up an experienced team of advisors to aid her and rebuild international confidence in Thailand.
"I would like the prime minister to show determination and be mindful in solving the problems," he said in an exclusive interview with The Standard.
Lt Gen Boonsin said he stood ready to follow any policy of his superiors "as long as it is a moral policy that fully benefits the nation."
The army commander responsible for the northeastern region is responsible for almost the entire land border with Cambodia. The government has handed him full authority to oversee all checkpoints bordering the neighbouring country.
Ms Paetongtarn stunned Thais when she called Lt Gen Boonsin a figure on the "opposite side" during her controversial conversation with former prime minister Hun Sen on Sunday. The clip of the 17-minute discussion went viral after it was released.
The clip has sparked a political uproar with protesters and the public demanding that the prime minister take responsibility by stepping down from power or dissolving parliament.
"The prime minister made an immediate phone call to me to apologise after that," he told The Standard in the interview.
The Second Army Region chief reaffirmed his loyalty to his superiors, ranging from armed forces commanders to the defence minister and prime minister.
"I would like the prime minister to clear this issue with the public," he said. "Don't worry about me."
The two will meet on Friday when Ms Paetongtarn visits Chong Bok, an area in Nam Yuen district in Ubon Ratchathanai province, to mend fences with the army officer.
Thai and Cambodian soldiers briefly clashed on May 28 after Lt Gen Boonsin confirmed that troops from the neighbouring country had moved up to 150 metres into Thai territory, built trenches and refused to retreat after several warnings.
He said it was the first time since 2011 that Cambodian security forces had advanced into the area.
Conditions for full border resumption
Lt Gen Boonsin said border checkpoints will not be fully returned to full operations until the two countries hold a Regional Border Committee (RBC) meeting.
The RBC is a mechanism chaired by Thai and Cambodian regional army commanders. Thailand has called for the meeting, but there has yet to be a response from Cambodia, according to him.
"Border checkpoints will not be fully opened. Let's have an RBC meeting first," Lt Gen Boonsin said.
The northeastern army leader said the regional meeting is vital as he hoped to see soldiers of the two countries end reinforcement of the entire border to cool down military tensions and reduce the risk of possible clashes.
"This is the reason why we will not yet open checkpoints 100%," he told The Standard.