Relations between Thailand and Cambodia suffered a major blow on Wednesday after a leak of a telephone conversation between Thai Prime Minister Paetongtarn Shinawatra and influential former Cambodian premier Hun Sen that could further escalate tensions.

Tens of thousands of people gathered in Cambodia’s capital Phnom Penh on Wednesday for a march to show their solidarity with the government and military, amid soaring tensions with neighboring Thailand following a border row that erupted last month.

As we share a long border, we both know that we have to live and grow together,” Thailand’s then-Ambassador to Cambodia Panyarak Poolthup told Cambodia’s then-Prime Minister Hun Sen. “The political will is always there to resolve any issues that may arise.