U.S. Defence Secretary Robert Gates said Thursday that the Obama administration's effort in the eight-year-old war in Afghanistan is "only now beginning," despite eroding public support for the conflict.

Gates also said he disagrees with people who say it is time to get out of Afghanistan.

U.S. Defence Secretary Robert Gates, shown in this 2006 photo, said Thursday that this is not the time for the U.S. to get out of Afghanistan. (J. Scott Applewhite/Associated Press)"I absolutely do not think it is time to get out of Afghanistan and I think that the notion that you can conduct a purely counterterrorist kind of campaign and do it from a distance simply does not accord with reality," he said.

Several recent public opinion polls have shown declining support amongst Americans for the idea of sending more troops to the conflict and falling confidence in how the campaign is going.

"I don't believe that the war is slipping through the administration's fingers," Gates said. "The nation has been at war for eight years. The fact that Americans would be tired of having their sons and daughters at risk and in battle is not surprising."

Gates argued that President Barack Obama's new strategy in Afghanistan has not been given a chance to work.

"I think what is important to remember is the president's decisions on this strategy were only made at the very end of March; our new commander appeared on the scene in June," he said, adding that the extra troops Obama ordered are not even all there yet.

"So we are only now beginning to be in a position to have the assets in place and the strategy or the military approach in place to begin to implement the strategy," Gates said.

The new U.S. and NATO commander, Gen. Stanley McChrystal, delivered a classified assessment Monday of how the war is going and is expected in the coming weeks to ask for more troops and money to turn the war around.

Obama is reading the report during his vacation at the Camp David presidential retreat north of Washington, his aides said.

At the Pentagon news conference, neither Gates nor the Joint Chiefs of Staff chairman, Adm. Mike Mullen, responded to a question about what the still-classified McChrystal report concludes.

But they repeatedly made references to some of the general's recommendations, with Mullen calling it a "frank and candid" look at how military forces can accomplish the Afghanistan mission.

With files from The Associated Press