South Korea on Sunday raised the travel alert for border regions in Cambodia and Thailand, the second adjustment of travel warning in three days, as the tension

The updated U.S. travel advisory comes amid concerns over an escalation of a long-standing dispute between the two Southeast Asian neighbors who share a 500-mile land border—largely mapped by France when it ruled Cambodia for 90 years until 1953.

Australian travellers have been warned to exercise a “high degree of caution” in Thailand “due to security and safety risks” amid an escalating border conflict with Cambodia that has left at least 33 people dead.

Conflict over an ongoing border dispute between Thailand and Cambodia has increased the security risk near the two countries’ border. Here’s what travellers need to know.