PHNOM PENH – On Wednesday, tens of thousands gathered in Phnom Penh, Cambodia’s capital, for a march demonstrating solidarity with the government and military amidst rising tensions with Thailand following a border conflict last month.

Here’s what to know about the latest dispute between the two Southeast Asian neighbors.

What was the latest conflict about?

The recent conflict commenced in May when Thai and Cambodian armed forces briefly exchanged fire over a relatively small “no man’s land” along their border, claimed by both nations.

Both sides have said they acted in self-defense. One Cambodian soldier was killed.

Despite agreeing to de-escalate afterward, Cambodian and Thai authorities continue to impose or threaten non-army measures against each other, maintaining high tensions.

Thailand has added restrictions at the border such as limiting crossing times and barring Thai casino tourists and workers from crossing into Cambodia.

Cambodia has banned Thai movies and TV shows, stopped the import of Thai fruits and vegetables and boycotted its neighbor’s international internet links and power supply.

How long have the two fought over land?

Border disputes are long-standing issues that have caused periodic tensions between the two neighbors. Thailand and Cambodia share more than 800 kilometers (500 miles) of land border.

The contesting claims stem largely from a 1907 map drawn under French colonial rule that was used to separate Cambodia from Thailand.

Cambodia has been using the map as a reference to claim territory, while Thailand has argued the map is inaccurate.

In February, Cambodian troops and their family members entered an ancient temple along the border in one of the disputed areas and sang the Cambodian national anthem, leading to a brief argument with Thai troops.

The most prominent and violent conflicts broke out around the 1,000-year-old Preah Vihear temple.

In 1962, the International Court of Justice (ICJ) awarded sovereignty over the area to Cambodia and that became a major irritant in relations.

Cambodia went back to the court in 2011, following several clashes between its army and Thai forces which killed about 20 and displaced thousands of people. The court reaffirmed the ruling in 2013, a decision that still rattled Thailand.

What happens next?

Similar to the Phear Vihear area, Cambodia is seeking a ruling again from the ICJ over several disputed areas, including where the deadly clash happened.

Thailand has said it doesn’t accept the jurisdiction of the ICJ and that any conflicting border claims between the two should be solved by the existing bilateral mechanism, including a joint committee which was established in 2000 as a technical means to discuss the survey and demarcation of the land border.

Cambodia nevertheless said it has submitted the case to the ICJ, and insisted that it would no longer discuss these areas under the two countries’ bilateral mechanism.

Tensions have soared as they engaged in a war of words that appeared intended to mollify nationalistic critics on both sides of the border.

Bickering neighbors

The ill feeling between the two neighbors is not just about overlapping border claims, but also deep-seated cultural enmity that has its roots from centuries ago, when they were large and competing empires.

In more modern times, bad feelings have lingered, as Cambodia’s development, hindered by French colonialism and, in the 1970s, the brutal rule of the communist Khmer Rouge, has fallen well behind Thailand.

Both have fought over claims on cultural products ranging from boxing, mask dancing, traditional clothing and food.

—— Jintamas Saksornchai reported from Bangkok