While it is rare for trading to be interrupted by the exchange's circuit breakers, it is particularly unusual for it to happen twice in one session, reflecting the pace and size of the selling overnight, traders said.

CME stopped trading in the most-active August futures contract at 9:29:03 p.m. EDT as part of a so-called "stop logic event".

That prevents cascading stop orders that could exaggerate price movements in illiquid markets.

The second halt started 29 seconds later and was part of a "velocity logic", which introduces a pause to matching of futures and options trades. During this pause, customers can submit, modify and cancel orders.

Some of the biggest price moves in gold futures in recent years have occurred during Asian hours, when liquidity is lower.

(Reporting by Josephine Mason; Editing by Peter Galloway)