BANGKOK -- Eleven Thai people were killed and 28 others injured in military clashes near the Thailand-Cambodia border on Thursday, acting Thai Prime Minister Phumtham Wechayachai said.

Speaking to reporters following a National Security Council meeting, Phumtham said heavy weapons were used by the Cambodian side in the clash.

"We remain committed to peaceful means and dialogue to resolve the problem. However, we must defend ourselves and protect our nation's sovereignty," Phumtham said.

Thailand's Ministry of Interior has carried out the evacuation of people from at-risk areas, Phumtham said, adding that for the safety of students, the Thai Ministry of Education has ordered the closure of schools in the affected border areas.

Thailand's Ministry of Public Health has converted district hospitals near the border into field hospitals and has evacuated patients to safer areas behind the front lines, said the Thai acting prime minister.

The situation escalated following skirmishes that began Thursday morning. The two sides both blamed the other side for initiating the firing.

Cambodian Prime Minister Hun Manet called on Thailand to immediately cease all hostilities, withdraw its forces to its side of the border, and refrain from any further provocative actions which could escalate the situation.

Hun Manet accused Thailand of violating the basic principles of international law.