World leaders are meeting with President Obama in his hometown of Chicago for a two-day NATO summit focused heavily on Afghanistan.

Obama warned of the difficulty ahead as the summit confronted questions about Afghanistan's future. The summit kicked off on Sunday with a meeting between Obama and Afghanistan's President Hamid Karzai, the two key players to determine that future.

"We still have a lot of work to do and there will be great challenges ahead," Obama said. "The loss of life continues in Afghanistan and there will be hard days ahead."

Chicago is bracing for another round of demonstrations on the last day of the NATO summit. Protesters say they'll march to Boeing headquarters this morning to voice their opposition to the company's role in the U-S. military.