Thailand's acting Prime Minister Phumtham Vejjaichai accused Cambodia of a lack of "goodwill" today, Agence France-Presse reported, BTA reported.
The agency notes that Vejjaichai made the remarks ahead of a planned meeting with his Cambodian counterpart in Malaysia for ceasefire talks today, on the fifth day since the start of bloody clashes between the two countries.
"We do not think Cambodia is acting in good faith, given their actions to resolve the problem. They need to show sincere intent," the leader told journalists at Bangkok airport.
"We need bilateral talks to negotiate an end to the fighting. However, a ceasefire does not mean everything will return to the previous state," he warned.
Cambodia said this morning that the opposing side had launched an attack near disputed temples in the northwest of the country.
"At 03:10 this morning (20:10 GMT yesterday), Thai forces attacked first again," said Cambodian Defense Ministry spokeswoman Mali Socheata. "This is the fifth day that Thailand has invaded Cambodian territory with heavy weapons and deployed a large number of soldiers," she added.
AFP journalists in Samrong, northwestern Cambodia, about 20 kilometers from the border, also heard the sound of artillery fire last night.
The Thai army said last night that it expected a "large-scale military operation" from the other side, reporting fighting in seven different locations.
The leaders of Thailand and Cambodia are expected to meet in Malaysia on Monday to try to ease tensions after clashes along their shared border. Bangkok said Prime Minister Vejjajaj would meet his Cambodian counterpart Hun Sen in Malaysia's administrative capital, Putrajaya, at 3 p.m. local time (07:00 GMT).
Earlier today, US Secretary of State Marco Rubio announced that State Department officials were in Malaysia to assist in the peace process.
Thailand and Cambodia have been in conflict for decades over the outlines of their common border, which was drawn during the French Indochina era. However, there has been no such outbreak of violence in the region since 2011. The artillery shelling and air strikes since Thursday have killed at least 35 people and forced about 200,000 to flee their homes, AFP recalls.