US President Barack Obama said in Washington on Tuesday that he will announce his administration's decision on a buildup of US forces in Afghanistan "shortly".

US President Barack Obama (R) and Indian Prime Minister Manmoham Singh hold a joint news conference in the East Room of the White House in Washington, D.C., capital of the US, Nov. 24, 2009. [Zhang Yan/Xinhua]

Speaking at a joint appearance with visiting Indian Prime Minister Manmohan Singh at the White House, Obama said he is intended to "finish the job" in Afghanistan.

Without disclosing the specific date for the announcement of the decision, the president predicted that the American public will be "extremely supportive" of the decision.

Obama added that the decision will also include civilian and diplomatic efforts.

The White House said earlier in the day that the president is expected to announce the Afghan decision "within days."

"After completing a rigorous final meeting, President Obama has the information he wants and needs to make his decision and he will announce that decision within days," White House Press Secretary Robert Gibbs said in a statement.

Meanwhile, US media are reporting that the president will announce the decision through an address to the nation next Tuesday, Dec. 1, likely in prime time.

Although the exact decision remains unclear, Obama is expected by analysts, media and officials to announce an increase of 10,000 to 40,000 troops in Afghanistan.

As the public is turning negative toward the Afghan war and his fellow Democrats are increasingly vocal in their opposition to a troop buildup in Afghanistan, the incoming decision is regarded as one of the most critical moments to shape Obama's presidency.