New Delhi, July 24 -- Thailand said Wednesday it is closing northeastern border crossings with Cambodia, withdrawing its ambassador to the neighboring country and expelling the Cambodian ambassador to protest a landmine blast in which a Thai soldier lost a leg.

A Thai Army statement said four other soldiers also were wounded Wednesday when one of them stepped on a land mine that Thailand blamed on Cambodia and said took place in Thailand's Ubon Ratchathani province.

Cambodia disputed that account, saying the blast happened in its Preah Vihear province. It occurred in one of several small patches of land along the border that both lay claim to and which is treated as a no-man's land.

The explosion drew a swift response from the Thai gov...