US President Barack Obama has said he will "never rush" a decision to send more troops to Afghanistan, as he comes under pressure to set out a new policy, BBC reported.
Speaking to servicemen and women at a Florida naval base, Mr Obama said he would not risk their lives "unless it is absolutely necessary".
Earlier, he met his national security team again for talks on Afghan policy.
Correspondents say Mr Obama's words may be a response to ex-Vice-President Dick Cheney's suggestion he was "dithering".
The White House has said a decision on a new strategy for Afghanistan, including troop numbers, will be made in the coming weeks, but critics say the process is taking too long.
The top US military commander in Afghanistan, General Stanley McChrystal, has asked for at least 40,000 more US troops there.
Meanwhile, Afghanistan's incumbent President Hamid Karzai and his election challenger Abdullah Abdullah are preparing for a run-off vote due to take place on 7 November.
'Gross mishandling'
Speaking at Jacksonville Naval Air Station in Florida, Mr Obama said: "I will never rush the solemn decision of sending you into harm's way."
He also promised that if it was necessary to send servicemen to war, the US would back them "up to the hilt".
"Because you deserve the strategy, the clear mission, the defined goals, as well as the equipment and support you need to get the job done," he said.
Earlier, he had held a sixth meeting with his national security advisers at the White House to discuss policy options.
Mr Cheney said last week: "The White House must stop dithering while America's armed forces are in danger.
"It's time for President Obama to do what it takes to win a war he has repeatedly and rightly called a war of necessity."
Democratic Senator John Kerry - who was with Mr Karzai in Kabul last week when he announced there would be a run-off vote - responded on Monday with his own attack on Afghan policy under Republican President George W Bush and Mr Cheney.
Speaking to the Council of Foreign Relations think tank in Washington, he accused the Bush administration of "grossly mishandling" the Afghan war.
He said the Bush administration had left a terrible inheritance in Afghanistan, which Mr Obama had tackled "on day one".
"After eight years of neglecting Afghanistan as vice-president, Dick Cheney has now come out of retirement to criticise President Obama for taking the time to examine assumptions before sending troops into war," Mr Kerry said.