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.

The UK’s Foreign, Commonwealth and Development Office (FCDO) has issued travel advisories to Thailand and Cambodia after the two countries exchanged rocket and artillery fire across several sights.

In its travel advice for Cambodia, the UK’s Foreign, Commonwealth & Development Office ( FCDO) has advised against all but essential travel within 50km from the border with Thailand in Oddar Meanchey and Preah Vihear provinces.

The Ministry of External Affairs also urged Indian travellers in both countries to contact embassies in case they needed any assistance.

Cambodia has accused Thai forces of breaching a previous agreement by crossing into Cambodian territory and carrying out what it describes as “unprovoked and deliberate attacks” near disputed temple areas.

Rising political unrest in parts of Thailand and Cambodia has prompted the Canadian government to update its travel advisory.