Thailand said at least one civilian was killed amid fresh clashes Thursday in multiple contested border areas with Cambodia after the nations downgraded their diplomatic relations in a rapidly escalating dispute.

Thai and Cambodian leaders are meeting in Malaysia in an urgent effort to resolve deadly border clashes that entered a fifth day despite mounting international calls for peace.

The Thai army said in a statement that Cambodia had conducted attacks at multiple locations early on Tuesday in violation of the ceasefire and Thailand had retaliated proportionately in self defence.