BANGKOK -- Armed clashes have broken out between Thailand and Cambodia in long-disputed border areas, rapidly escalating months-long tensions.

Thailand said its navy joined the army in repelling Cambodian attacks along the border, as fighting spread to new areas on the third day of a conflict that has killed more than 30 people.

A threat by President Donald Trump to halt trade negotiations with both Cambodia and Thailand until a truce had been reached forced both sides to the negotiating table. Even so, the ceasefire looks shaky.