Adds response from CME Group in paragraph 2

June 22 (Reuters) - Derivatives exchange operator CME Group CME.O said on Monday that it has resolved connection issues faced by some of its direct customers earlier in the day.

"Due to a third-party network issue, some CME Direct clients experienced disconnects at about 1:00 p.m. Central Time. Some affected clients also experienced delays reconnecting," a spokesperson for the company told Reuters.

CME Globex, the system that powers all futures and options trading, remained unaffected, the spokesperson said.

The issue caused a brief trading disruption and affected oil, natural gas, copper, gold and silver, Bloomberg News reported earlier in the day, citing unidentified traders.