UPDATE 1-More troops sent in Thai-Cambodia temple dispute

(Adds Cambodia's petition U.N. Security Council)

By Nopporn Wong-Anan

KANTARALAK, Thailand, July 19 (Reuters) - Thailand and Cambodia sent troops and heavy guns on Saturday to their disputed border, where hundreds of soldiers faced off for a fifth day over an ancient Hindu temple.

Despite the military build-up, both sides said they were ready to negotiate an end to the stand-off.

The dispute has raised investor fears of a major confrontation. Thailand's main stock index has fallen more than 23 percent since anti-government street protests in Bangkok began in late May, and could drop further if border tensions get worse, analysts said.

The Preah Vihear temple, perched on a jungle-clad escarpment that forms a natural boundary, has been a source of tension since the International Court of Justice ruled in 1962 it belonged to Cambodia, a decision that still rankles Thais.

The listing of Preah Vihear as a World Heritage site this month triggered a political uproar in Thailand, stoked by groups opposed to Prime Minister Samak Sundaravej whom they accuse of being a proxy of former Prime Minister Thaksin Shinawatra, who was ousted in a 2006 coup.

The diplomatic sparring between Bangkok and Phnom Penh has intensified ahead of high-level talks on Monday involving the two countries' defence ministers.

Thailand summoned Cambodia's ambassador on Friday to respond to Prime Minister Hun Sen's charge that Thai troops had "encroached" on Cambodian territory" and that the situation was "worsening".  Continued...