By Frank Tang and Christopher Doering

NEW YORK/WASHINGTON, March 23 (Reuters) – The top U.S. futures regulator, which has struggled to gain support for a plan to curb concentration in energy markets, could face even tougher resistance on Thursday as it considers whether similar provisions are needed for metals.

The Commodity Futures Trading Commission will hold a day-long hearing to determine whether it needs to write a rule to create speculative position limits for gold, silver and copper markets to prevent price manipulation.

Commissioners will hear from metals markets players who oppose position limits and are expected to argue that limits will drive trade to unregulated or overseas markets.

A group of gold and silver “bugs” who believe governments and banks artificially depress precious metals prices are expected to ask the commission to prevent price manipulation in metals markets.

Bart Chilton — one of five CFTC commissioners and the most outspoken in favor of position limits across all commodities of finite supply — tamped down support for metals curbs ahead of the hearing, but said he remained optimistic.