A Thai lawmaker and six other Thai nationals face up to 18 months in prison after being charged in Phnom Penh Municipal Court yesterday following their arrest for trespassing near the contentious Thai-Cambodian border.

Panich Vikitsreth, an MP from Thailand’s ruling Democrat Party, was among a group of seven people charged with illegal entry and unlawfully entering a military base, Phnom Penh deputy prosecutor Sok Roeun said. The group was questioned yesterday after being apprehended near a military encampment in Banteay Meanchey province on Wednesday, across the border from Thailand’s Sa Kaeo province.

Thai Prime Minister Abhisit Vejjajiva admitted he had tasked Panich with investigating the border and called for the case to be dismissed.

“Cambodia must release all seven Thais immediately,” Abhisit said. “Cambodia must take into consideration that if they want cordial ties, they should rely on negotiations. If not, then there is a problem for both sides.”

Abhisit assigned Thai foreign minister Kasit Piromya with travelling to Cambodia and meeting with Cambodian Minister of Foreign Affairs Hor Namhong in a bid to secure the group’s release. Following the meeting, however, Hor Namhong told reporters that the case would proceed.

“While the court process is ongoing, the government cannot do anything,” Hor Namhong said. Prime Minister Hun Sen addressed the case in a speech on Wednesday, saying Thai lawmakers “have parliamentary immunity in Thailand, but not in Cambodia”.

Kasit said through a translator that the incident would not create broader conflict between Thailand and Cambodia.

“We respect the judiciary of Cambodia,” he said. “We have proposed to the [Cambodian] government that they complete this case as soon as possible.”

Arrested along with Panich was Veera Somkwamkid, a former leader of the “Yellow Shirt” People’s Alliance for Democracy who now leads the Thailand Patriot Network, a PAD splinter group. Veera and the PAD have staged repeated rallies along the border to protest against alleged Cambodian encroachment.

PAD spokesman Panthep Puapongpan said Wednesday that the group had gone to “investigate the demarcation area between Thailand and Cambodia”, claiming they were apprehended on Thai soil.

“We request that the Cambodian government officially, from Hun Sen, must apologise to the Thai people and to the Thai government,” Panthep said. “Cambodia has tried to invade us and hold the territory that belongs to us.”

Thai deputy prime minister Suthep Thaugsuban acknowledged, however, that the group was arrested in Cambodia.

“Panich and his entourage passed the border police checkpoint and border police followed them by car to ask them to return, but they were already on Cambodian soil,” Suthep said.

Panich, Veera and their fellow defendants wore solemn expressions as they were led into their hearing yesterday, which was closed to reporters. The seven are being held in Prey Sar prison, with their trial date yet to be scheduled.

Back in Banteay Meanchey, provincial governor Ung Oeun said he had ordered all border crossings closed save for the Poipet International Border Checkpoint.

In Preah Vihear province, two Cambodian villagers were arrested yesterday along the border by Thai soldiers, said Dy Phen, director of the border relations office in Banteay Meanchey.

“I have sent my forces to negotiate with the Thai side and have those two villagers released, because they were just scavenging in the forest and did not know where the border line was,” he said.

Panich’s case marks the latest turn in the long-standing border dispute between Thailand and Cambodia, which heated up in 2008 when Preah Vihear temple was enshrined as a UNESCO World Heritage Site for the Kingdom. A bilateral demarcation plan is in progress, though it has been stalled since last year pending approval of the latest round of negotiations in the Thai parliament. ADDITIONAL REPORTING BY AFP AND SAM RITH