President Obama plans to speak on the future of the U.S. mission in Afghanistan on Wednesday, senior administration officials said Monday.

The president is expected to announce his decision on the level of troop withdrawals, though he has yet to decide the size and scope of that withdrawal. Obama has only said the initial drawdown will be significant. Some have privately estimated that could mean 3,000 to 5,000 troops initially and an equal number by the end of the year, Reuters reported.

Defense Secretary Robert Gates, backed by the Pentagon, has urged a modest drawdown of the 100,000 U.S. troops now in Afghanistan, for fear of undercutting progress on the ground that he has warned is fragile and reversible.

But the president is still finalizing his decision. He's reviewing his options, said White House Press Secretary Jay Carney at his daily briefing Monday.

While the location for Obama's Wednesday speech was not disclosed, the president is scheduled to visit Ft. Drum in upstate New York on Thursday. Ft. Drum is home to the 10th Mountain Division, one of the most deployed divisions to Afghanistan and Iraq.

Carney would not say if the announcement would take place during that visit.

There are currently 100,000 troops in Afghanistan, 30,000 of which are considered part of the president's 2009 surge to stabilize the country. When President Obama announced the soldier increase, he said that additional forces will allow us to accelerate handing over responsibility to Afghan forces, and allow us to begin the transfer of our forces out of Afghanistan in July of 2011. Just as we have done in Iraq, we will execute this transition responsibly, taking into account conditions on the ground.

Obama promised to start bringing U.S. troops home by next month, and he has been in the process of deciding the number of troops. Carney said the president's decision would be motivated by an assessment of the success of the mission to this point.

There has been significant progress in disrupting, or halting, the momentum of the Taliban, and significant progress in stabilizing Afghanistan and the government to allow Afghan national security forces to build up, to train and prepare for taking over the lead, Carney said. So he looks at this decision as a part of a process, of a policy he put in motion.