There was a fresh exchange of artillery fire Sunday along the border separating Thailand and Cambodia following two days of clashes that left at least 10 soldiers dead and forced thousands of civilians to evacuate.
No one was reported killed on Sunday.
The two southeast Asian neighbors are in dispute over a small area of land that surrounds Cambodia's 900-year-old Preah Vihear temple. Border clashes have erupted several times since 2008 when the temple was given U.N. World Heritage status, over Thailand's objections.
This latest outbreak, which each country blames the other for starting, follows a four-day battle in February that killed nearly a dozen soldiers.
U.N. Secretary-General Ban Ki-moon has called for a cease-fire. Indonesia is to continue mediation efforts on Monday when its Foreign Minister Marty Natalegawa travels to the region for talks. Indonesia, along with Thailand and Cambodia, is a member of the Association of Southeast Asian Nations.
On Sunday, Cambodia accused Thailand of firing shells "loaded with poisonous gas" and cluster munitions which are banned by many countries. Thailand called the allegations "groundless."
There has been no clear explanation for this year's resumption of border clashes. But there is speculation that the Thai government may be raising its military profile ahead of parliamentary elections expected in July.
Some information for this report was provided by AP, AFP and Reuters.