(Adds ICE comment)

NEW YORK, Nov 20 (Reuters) - The ICE Futures Exchange on Friday canceled trades on the U.S. dollar index futures, the second time it did so this month, but provided few details.

The exchange canceled trades in the December contract above 76.50, a spokesperson said.

It was the second time this month that the ICE canceled trades on the December futures dollar index.

Traders on Friday said the December futures contract DZX9 on the index had spiked to 82, raising questions given that the dollar's rise versus the euro EUR= was below 1 percent. The euro is the biggest component of the index, with a weight of 57.6 percent.

“That fact that this has occurred on two specific occasions within a two-week time frame leads market participants to believe that there is some suspicious (cancellation) of legitimate trades by the ICE Exchange,” said Mike Hill, a partner at private investment house USF Corp in Atlanta, Georgia.

Lee Underwood, communications director at ICE in Atlanta, said in a statement: “All trade cancellations are made pursuant to the exchange rulebook.”

According to estimates from market participants, about 4,000 contracts were canceled on Friday. The ICE declined to give the exact number.

Sources said the trades affected were those that came in between 7:04 a.m. to 7:07 a.m. ET.

The ICE had also canceled trades on the December futures dollar index on Nov. 3, between 4:59 a.m. to 5:07 a.m. ET, a market source said, adding that around 8,000 contracts were canceled.

The ICE on Nov. 3 also had declined to give specific information about the volume or reason why the trades were canceled.

Late afternoon in New York, the ICE Futures December dollar index contract was up 0.5 percent at 75.710. Meanwhile, the Reuters-calculated dollar index, which measures the dollar's value against a basket of six other major currencies, was up 0.5 percent at 75.637 .DXY. (Reporting by Gertrude Chavez-Dreyfuss; Editing by Leslie Adler)