Thailand's military said it has collected "worrying" signs that Cambodia has stepped up military preparations.

Thailand's military said it was ready to launch a "high-level action" to resist its sovereignty and made its strongest comments after a long-standing border dispute with Cambodia re-emerges.

The Thai military said in a statement Thursday night that its intelligence had gathered "worrying" signs that Cambodia had strengthened its military preparations on the common border.

"Now, the Army is ready to conduct high-level military operations in case there is a need to retaliate against violations of sovereignty," the statement said.

The statement added: “United units operations at the border have been carried out carefully and calmly and based on an understanding of the situation to prevent losses from parties, but at the same time, if such a situation is required, it is prepared to defend the country’s sovereignty to the greatest extent.”

The top armed forces of the Thai Armed Forces were scheduled to hold a closed-door meeting on Friday afternoon, while the country's army, navy and air force also improved combat readiness, according to the Thai Public Broadcasting Service (Thai PBS).

The Thai PBS also reported that Colonel Chainarong Kasee, commander of the 12th Infantry Regiment of Thailand, said his troops were ordered to check that all equipment were in good condition.

On May 28, the Cambodian Ministry of Defense said Thai troops fired and killed one of the soldiers in a brief firefight between Cambodia's Preah Vihear province and Thailand's Ubang Lanchasani province.

The ministry accused Thai soldiers of opening fire first at a Cambodian military post in the disputed border area. Thai Defense Minister Phumtham Wechayachai said Cambodian troops opened fire first.

Over the years, Southeast Asian neighbors have clashed repeatedly in the border area of ​​Preah Vihear, where a 900-year-old temple is located at the center of a decades-long dispute that has sparked nationalist sentiment on both sides of the border.

Between 2008, several deadly clashes occurred in the region - Cambodia registered the temple as a UNESCO World Heritage Site - in 2011, about 40 people were killed, including five civilians.

The 2013 ruling of the International Court of Justice (ICJ) upheld the 1962 ruling, which was granted by the same agency a portion of the land around Preah Vihear Temple and directed Thailand to withdraw its personnel stationed in the area.

Cambodia Prime Minister Hun Manet, son of long-time former leader Huns, said Cambodia will file disputes with the ICJ on four parts of the border to make a ruling and demand cooperation in Thailand in the process.

Thailand has not realized the jurisdiction of the ICJ since 1960 and instead calls for bilateral talks.

"Thailand and Cambodia already have existing bilateral mechanisms to address these issues," the Thai government said in a statement.

"Thailand reaffirms its position as a neighbor committed to a peaceful settlement of the problem and is based on international law, treaties and agreements … as well as satellite images and other verified evidence," the statement added.

Cambodia - A meeting of the United Border Commission of Thailand is scheduled for June 14.