WASHINGTON - President Barack Obama will unveil his long-awaited Afghanistan strategy in a prime-time address from West Point, N.Y., on Dec. 1, the White House said Wednesday, but the administration's advance remarks have sparked concern that talk of an eventual U.S. withdrawal will encourage Islamist insurgents to persevere.

During the speech, "The president will want to walk through his decision-making process and give people a sense of the importance of our efforts, but reiterate for them that ... (he) does not see this as an open-ended engagement," said White House spokesman Robert Gibbs. "Our time there will be limited, and I think that's important for people to understand."

In a sign that the insurgents may think they can outlast the U.S. and its allies, hours after Obama on Tuesday declared that he intended to end the war during his presidency, Taliban leader Mullah Mohammad Omar ruled out a political settlement and said his Islamist movement would "gain strength with the passage of time."

In a statement posted on a Taliban-run Web site, he also urged Afghans to join the fight against the U.S.-led coalition in Afghanistan.

"The foreigners have occupied the land of the Afghans by ... might and savagery. If they want (a) solution of the issue, they should put an end to the occupation of Afghanistan," said Omar, who's thought to be based in neighboring Pakistan. "The invading Americans want mujahedeen to surrender under the pretext of negotiation. This is something impossible."

To read full McClatchy News story — Go Here Now.