On Tuesday, Obama also pushed for a deeper partnership with Pakistan, saying that his administration recognizes that success in Afghanistan is "inextricably linked" to the U.S.-Pakistan relationship.
"We're in Afghanistan to prevent a cancer from once again spreading through that country. But this same cancer has also taken root in the border region of Pakistan. That's why we need a strategy that works on both sides of the border," the president said.
Obama said that his administration is committed to a partnership with Pakistan built on "mutual interests, mutual respect, and mutual trust," but Pakistani leaders must also do their part.
Pakistan's foreign ministry today released a statement saying "it looks forward to engaging closely with U.S. in understanding the full import of the new strategy and to ensure that there would be no adverse fallout on Pakistan." In recent days, the country's leaders have expressed skepticism of Obama's new plan.
Obama also touted the new strategy as an "international effort" with contributions from allies.
"Our friends have fought and bled and died alongside us in Afghanistan. Now, we must come together to end this war successfully," he said. "For what's at stake is not simply a test of NATO's credibility -- what's at stake is the security of our allies, and the common security of the world."
NATO Secretary General Anders Fogh Rasmussen said that he expects U.S. allies to contribute at least 5,000 additional troops next year, although he did not provide details. Britain has already announced the deployment of 500 more soldiers, but France and Germany have so far made no such commitment.
"This is our fight, together. We must finish it together," Rasmussen said at a news conference. "I can confirm that the allies and our partners will do more, substantially more. In 2010, the non-U.S. members of this mission will send at least 5,000 more soldiers to this operation, and probably a few thousand on top of that. That is in addition to the more than 38,000 they have already there."
ABC News' Jake Tapper, Karen Travers and Jim Sciutto contributed to this report.