GWEN IFILL: In other news today, the president of Iran, Mahmoud Ahmadinejad, challenged President Obama to a debate if he is re-elected next month as Iran's president. Ahmadinejad said it would take place at the U.N. General Assembly meeting in September. He said he'd like to discuss world peace and global security issues.
In Pakistan, the Taliban called for refugees to return to the main city in the Swat Valley. Government troops have targeted that region in a new offensive. The militants promised to stop fighting in Mingora. They said it's an effort to prevent civilian deaths.
A Pakistani army spokesman said the Taliban are using "ploys to escape. They are now remembering the civilians whom they used to behead and decapitate."
Millions of Americans paid tribute to the nation's fallen soldiers on this Memorial Day. President Obama laid his first wreath as commander-in-chief at Arlington National Cemetery. He said those in uniform represent the best of America, and he promised not to let them down.
PRESIDENT BARACK OBAMA: I know that there is nothing I will not do to keep our country safe, even as I face no harder decision than sending our men and women to war and no moment more difficult than writing a letter to the families of the fallen.
And that's why, as long as I am president, I will only send our troops into harm's way when it is absolutely necessary, and I will always provide them with the equipment and support they need to get the job done.
GWEN IFILL: Half a world away, in Afghanistan, U.S. troops in Kabul remembered those killed as recently as last week. Their commander called it an intensely personal day, with flowers and photos placed by helmets of the fallen.