The U.S. military's top uniformed officer is concerned about what he says is eroding public support for the war in Afghanistan.
Adm. Mike Mullen also says Afghanistan remains vulnerable to being taken over again by extremist forces.
The chairman of the Joint Chiefs of Staff says President Barack Obama's new strategy for defeating the Taliban and al-Qaida is still a work in progress as more U.S. troops are put in place. Mullen wouldn't say whether more American forces troops will be needed. The Obama administration is awaiting an assessment about the situation from the top U.S. commander in Afghanistan. That report is expected in about two weeks.
Mullen spoke on NBC's "Meet the Press."
Meanwhile, Sen. John McCain said in an interview for broadcast Sunday on ABC's "This Week" that he wants the military leadership in Afghanistan to use the same aggressive approach that Gen. David Petraeus used successfully in Iraq.
The Arizona Republican said Army Gen. Stanley McChrystal should say exactly how many troops he needs in Afghanistan, let the Congress debate it and that President Barack Obama would make the ultimate decision.
Troops in Afghanistan should "clear and hold" an environment for people so that economic and political progress can be made, he said. McCain said he worries McChrystal will be pressured to ask for lower troop totals than he needs.
On the question of what it will take to turn the tide in Afghanistan, McCain said: "I think within a year to 18 months you could start to see progress."
"We're facing a very determined enemy that will stand and fight in some instances that are very adaptable, and obviously with safe havens in Pakistan," he said. "But as the president described it in the campaign, this is a good war and one that we have to win. And I think he'll hold to that."
McCain acknowledged that public opinion on Afghanistan is slipping. But he said that opinion could be reversed. "I think you need to see a reversal of these very alarming and disturbing trends on attacks, casualties, areas of the country that the Taliban has increased control of."