SINGAPORE, May 18 (Reuters) - Gold fell on Thursday as the U.S. dollar retained most of its gains against other currencies, raising fears the metal's bull run may be coming to an end.

Silver dropped as much as 1.8 percent while palladium lost around $5 before rebounding. Platinum firmed as fund buying persisted in Tokyo Commodity Exchange but remained below Wednesday's record high of $1,336 an ounce.

Spot gold slipped to $687.50/688.25 an ounce from $690.90/691.70 late in New York. It briefly hit a high of $692.10 in Asian trade.

Benchmark gold futures <0#JAU:> on the Tokyo Commodity Exchange, currently April 2007, fell 24 yen per gram to 2,489 yen

($22.43), tracking losses in the U.S. market.

Gold, used in jewellery and investment, saw volatile trade on Wednesday, when it rose nearly 4 percent to hit a high of $716 before a firming dollar prompted profit taking.

"A rebound in the dollar was seen to draw investors away from some commodities and undermined the hopes that Monday's sharp fall was just a pause in a record run for the asset class," said N M Rothschild in a daily report.

"Indeed now, many analysts are beginning to say the extreme volatility and thin trade is a symptomatic of an overstretched market and suggest that we may have reached a peak for the metals," it said.

Gold and other commodities fell victim to speculative selling from record highs this week, falling to a one-week low of $674 before some physical demand helped it rebound.

Bullion has risen 33 percent since the start of the year and 64 percent from a year earlier.

"We see a break of $675 on the downside as significant and a possible trigger for more selling with $655, $620 and $600 the targets," said Rothschild.

"We feel for the present volatility will persist and movements in the currency and energy markets will offer fresh leads going forward," it said.

The dollar kept most of its gains after rising on comments from European officials the euro's gains in the past months could stymie economic growth in the region.

The dollar was at 110.90 yen in early trade, after surging to 111.35 yen on Wednesday when the U.S. currency posted its biggest one-day gain since June.

The euro was little changed at $1.2745 , after sliding 1.7 percent to around $1.27 the previous day.

"I think we need to crack $675.50 before we talk about those big numbers below. My outlook is more range trading of $670 to $730 until after the first half of the year if the going is good," said a bullion dealer in Singapore.

"For a complete sell-off, then every single one of those commodity and pension funds must change their mind and decide not to invest in gold anymore. That possibility seems a little remote," he said.

Platinum rose to $1,316/1,324 an ounce from $1,308/1,316 late in New York, aided by gains in Tokyo platinum futures given the metal's bullish outlook.

Precious metal refiner Johnson Matthey said in a closely watched report on Monday that platinum demand was expected to outpace supply in 2006.

Sister metal palladium also rose to $373/381 an ounce from $370/376.

Silver dropped to $13.14/13.24 an ounce from $13.29/13.44.

Precious Metals Prices by 0127 GMT*

Last Net change Pct Move

Gold 687.30 -2.20 -0.32

Platinum 1318.00 10.00 +0.76

Palladium 372.00 2.00 +0.54

Silver 13.14 -0.01 -0.08

Change so far in 2006

Metal Latest bid End prev year Pct Move

Gold 687.30 517.20 +32.89

Platinum 1318.00 968.00 +36.16

Palladium 372.00 254.00 +46.46

Silver 13.14 8.81 +49.15

* The closing prices used to calculate the net change may differ from New York's last quoted prices.

($1=110.95 yen)