Hillary Clinton, the US secretary of state, described the latest deployment as "an integrated military-civilian strategy."
"We are convinced that the most critical underpinning of any success we hope to achieve, along with the people and government of Afghanistan, will be looking at where civilian trainers, aid workers, technical assistance of all kinds can be best utilised," she said during a visit to Mexico.
US officials have said success in Afghanistan is impossible without tackling Taliban enclaves in Pakistan, whose government is beset by political turmoil.
"I'm still very concerned about the Pakistan component, and I think there's still some work to be done with respect to the Pakistan component," John Kerry, the Senate Foreign Relations Committee chairman, said about the new strategy.
Nabi Misdaq, an Afghanistan analyst in Washington, told Al Jazeera he hoped Obama would not go for a military solution to the conflict, citing a series of US airstrikes that have caused a number of civilian casualties.
"If these air strikes intensify ... people will take up arms against US troops."
Obama has said previously that the US is losing the war in Afghanistan and the new policy is central top his administration's efforts to turn the conflict around, giving more responsibility to the Afghan government itself.
Obama is to define the objectives of the plan as eliminating the threat from al-Qaeda to undermine or topple US-backed elected governments or to launch attacks on the United States, its interests and allies, the Associated Press reported sources as saying.
|Obama is set to announce a 'civilian surge' to accompany the troop increase [AFP]
Carl Levin, chairman of the Senate Armed Services Committee, said the training group was needed.
"We've got to increase the size (of the Afghan army) much more quickly than contemplated and the trainers are the key to that," said Levin, a Democrat.
The review also says the US will send hundreds more civilian advisers to Afghanistan, the Associated Press reported.
The "civilian surge" would concentrate on improving life for ordinary Afghans, and would include experts in agriculture in a country where subsistence farming is common.
The Obama strategy document deliberately avoids specific numbers, costs and timelines "in any domain," a senior defence official told the Associated Press.
The United Nations is due to hold a conference on Afghanistan in The Hague next week, attended by delegates from more than 80 countries.
The gathering was suggested by the US and will also be attended by representatives from Iran, which has said it sees a regional solution to the conflict as vital to securing a lasting peace.