BANGKOK - One Thai soldier was killed and three others injured in overnight clash with Cambodian troops near Ta Kwai temple on disputed border between Thailand's northeastern Surin province and Cambodia.

Related readings:  Clashes continue between Cambodian, Thai troops  Cambodian, Thai troops break truce

According to Army Region 2, the cross-border clash began at 8 pm Monday night after mortars were fired at a Thai military base, triggering proportionate retaliation from Thai side. Small arms, mortars and hand grenades were used by both sides in the conflict but no heavy weapons were used.

Sporadic gunfire exchanges continued till 2.30 am on Tuesday.

The deadly border conflict since April 22 has brought the death toll to 18 including nine Cambodian soldiers, eight Thai soldiers and one Thai civilian.

Villagers who had just returned to their homes on Monday ran for their lives to shelter.

The clash occurred despite a ceasefire agreement reached between field commanders of both countries.

Over 100,000 residents in the two countries were displaced following the latest round of border clash.