Cambodian Defense Ministry spokesperson Lt. Gen. Maly Socheata accused Thai forces of escalating the violence with bombardment of Cambodian territory early Sunday, followed by a “large-scale incursion” involving tanks and ground troops in multiple areas.

Thailand and Cambodia have bickered for decades over undemarcated points along their 817-km (508-mile) land border, with ownership of the ancient Hindu temples Ta Moan Thom and the 11th century Preah Vihear central to the disputes.

Thailand and Cambodia will hold talks in Malaysia to address a deadly border dispute spurred by recent hostilities. Prompted by U.S. intervention, both nations expressed tentative agreement to a ceasefire.