"It was here, in Afghanistan, where Osama bin Laden established a safe-haven for his terrorist organization. It was here, in Afghanistan, where al Qaeda brought new recruits, trained them, and plotted acts of terror. It was here, from within these borders, that al Qaeda launched the attacks that killed nearly 3,000 innocent men, women and children," Obama said.
"Ten years ago, the United States and our allies went to war to make sure that al Qaeda could never again use this country to launch attacks against us. Despite initial success, for a number of reasons, this war has taken longer than most anticipated," he said.
Obama cited safe-havens in Pakistan, Taliban insurgency and years fighting in Iraq for the longer than expected war.
Read more about the president's speech in Afghanistan.