WASHINGTON — President Obama plans to announce his decision on the scale and pace of troop withdrawals from Afghanistan in a speech from the White House at 8 p.m. Eastern time Wednesday evening.

As he prepares to reveal the decision, a White House official said Mr. Obama was considering options that ranged from a Pentagon-backed proposal to pull out only 5,000 troops this year to an aggressive plan to withdraw within 12 months all 30,000 of the additional troops that the United States deployed to Afghanistan as part of the surge in December 2009.

Under another option, another official said, Mr. Obama would announce a final date for the withdrawal of all the surge forces sometime in 2012, but leave the timetable for incremental reductions up to commanders in the field — much as he did in drawing down troops after the surge in Iraq.

Planning for a rollout of the announcement was well under way, with Secretary of State Hillary Rodham Clinton scheduled to testify Thursday before the Senate Foreign Relations Committee and Mr. Obama due to visit Fort Drum in upstate New York, the home of the Army's 10th Mountain Division, which has been deployed to Iraq and Afghanistan in recent years.