The number of U.S. troops remaining in Iraq in 2006 will be determined by the insurgency as well as the capabilities of Iraqi forces, the chairman of the Joint Chiefs of Staff said Sunday.

Gen. Peter Pace said the United States does not have a specific goal for troop numbers, but rather "off-ramps and on-ramps based on what we have on the ground."

"The enemy has a vote on this," Pace said on "FOX News Sunday."

He said that if Americans were looking at a color-coded map of deployments next year, they'll "see the map and watch the colors change" as Iraqi battalions take over for U.S. forces.

However, he cautioned that the U.S. military needs to be flexible enough to increase forces to handle specific security problems that might arise.

Defense Secretary Donald H. Rumsfeld announced during a trip to Iraq this past week that President Bush has authorized new cuts in U.S. combat troops in Iraq, below the 138,000 level that prevailed for most of this year.

Rumsfeld did not reveal the exact size of the troop cut, but Pentagon officials have said it could be as much as 7,000 combat troops.

"The effect of these adjustments will reduce forces in Iraq by the spring of 2006 below the current high of 160,000 during the (Iraqi) election period to below the 138,000 baseline that had existed before the most recent elections," Rumsfeld said.

Gen. George Casey, the top U.S. commander in Iraq, told reporters after Rumsfeld announced the troops cuts Friday that he hopes to recommend more reductions as early as next spring -- assuming progress such as formation of an Iraqi government.

But Casey added, "I don't have a goal for the end of 2006."

Former Secretary of State Colin Powell, appearing on ABC's "This Week," said he was "quite sure" the number of U.S. troops in Iraq would decrease in 2006.

"One, I don't think we can sustain this level of presence with the size force that we have," Powell said. "You can't keep sending them back over and over."

Powell also said "we're well on our way" to building up the Iraqi military and police forces to take over for U.S. troops.

Pace said Sunday he was pleased that re-enlistment rates among troops serving in Iraq and Afghanistan were "higher than in all the armed forces" as a whole.

"They know what they're doing is appreciated by the Iraqis and the Afghan people," he said.

The Army exceeded its recruiting goal in November, the sixth consecutive on-target month, but it has fallen off the pace for meeting its re-enlistment goal for the year, the Pentagon has said.

The Navy, Air Force and Marine Corps also exceeded their recruiting goals in November, although their targets are much lower than the Army, which is aiming to sign up 80,000 new active-duty soldiers during the budget year that ends Sept. 30, 2006.

Army officials have said they expect this to be an extremely difficult year for recruiting, in part because of the Iraq war. In the budget year that ended Sept. 30, the Army fell more than 6,600 recruits short, or about 8 percent below its target of 80,000, although it pointed to strong re-enlistment as a sign that young soldiers find their work rewarding amid speculation that wartime duty is putting too much stress on soldiers.