A Thai parliamentarian and six other Thai nationals were questioned by a Cambodian court Thursday after being arrested along the border for alleged trespassing, according to dpa. Panich Vikitsreth of the ruling Democrat Party was arrested along with the six other Thais Wednesday in a disputed border area between Thailand's Sa Keow province and Cambodia's Banteay Meanchey province. Thai Prime Minister Abhisit Vejjajiva said Thursday that the seven men should be released immediately and dispatched Foreign Minister Kasit Piromya to Phnom Penh to seek their freedom. Abhisit noted that both countries had previously agreed there should be no soldiers in the disputed area where the Thais had been arrested. The men visited the border area Wednesday to check on reports that Cambodian soldiers had moved in to villages claimed by Thailand, according to Thai government sources. Cambodian Prime Minister Hun Sen said late Wednesday that the case would proceed quickly, adding that he had rebuffed requests from Thai officials to intervene. "I think Prime Minister Abhisit will understand Cambodian legal procedure, which no one can abuse," Hun Sen said, adding that the group "will face legal punishment because Thai lawmakers cannot use their parliamentary immunity in Cambodia." A senior Cambodian official said the group was being held for "trespassing under immigration law." "They intruded into Cambodia," the official said, requesting anonymity because he was not authorized to speak on the matter. The court hearing Thursday was closed to reporters although it was attended by the Thai ambassador to Phnom Penh, Prasas Prasavinitchai. One of the Thais on trial, Veera Somkwamkit, was previously arrested for illegally entering Cambodia to protest Cambodian soldiers' occupation of Preah Vihear temple, the source of another border dispute between the two countries. Kasit was scheduled to meet with his counterpart, Foreign Minister Hor Namhong, in the Cambodian capital later Thursday. Relations between Thailand and Cambodia have been tense for more than two years with sporadic clashes between troops over disputed territory surrounding Preah Vihear, 200 kilometres east of Banteay Meanchey. The 11th-century Hindu temple, known as Preah Vihear in Cambodia and Phra Viharn in Thailand, belongs to Cambodia under a 1962 ruling by the International Court of Justice, but jurisdiction of 4.6 square kilometres of adjacent land is still in dispute. The two countries are currently demarcating their border although talks have been stalled pending a repeatedly delayed vote in the Thai parliament to approve the latest round of negotiations.