BANGKOK, Thailand (AFP) — Thailand temporarily closed its biggest border crossing with Cambodia to local tourists on Saturday after a Cambodian soldier was killed in a recent military clash between the two uneasy neighbors.

There has been sporadic violence on the Thai-Cambodia frontier since fighting first broke out in 2008, resulting in at least 28 deaths.

A Cambodian soldier was killed in the most recent outbreak on 28 May in an area known as the Emerald Triangle, where the borders of Cambodia, Thailand and Laos meet.

The Thai and Cambodian militaries agreed to ease tensions the following day but Cambodia then said it would keep its troops in the area, despite Thailand urging it to withdraw.

The Royal Thai Army took control of the “opening and closing” of all border crossings it shares with Cambodia on Saturday, citing a “threat to Thailand’s sovereignty and security.”

The 1st Army Region banned the passage of six-wheeled trucks and reduced the operating hours of the border crossing between Aranyaprathet in Thailand’s southeast and Poipet in Cambodia’s west.

It said in a statement on Saturday that Thais and Cambodians would only be allowed to cross for work and trade purposes.

The Aranyaprathet-Poipet border crossing sees the most land traffic between the two countries with several thousand people using it each day, many of them Thais going to gamble at casinos on the Cambodian side.

The Royal Thai Army told Agence France-Presse that the restrictions only applied to citizens of the two countries but that implementation “may vary from place to place.”

Six other border checkpoints tightened their opening hours and issued bans on six-wheeled vehicles.