President Obama listens to Pakistani Prime Minister Syed Yusuf Raza during their bilateral meeting on the sidelines of the Nuclear Security Summit in Seoul, South Korea, on Tuesday.
Obama talks with Canadian Prime Minister Stephen Harper (second from right) before the start of the plenary session of the Nuclear Security Summit.
Japanese Prime Minister Yoshihiko Noda meets with Obama during a working luncheon of the Nuclear Security Summit.
Obama talks with Israeli Deputy Prime Minister Dan Meridor (left) at the summit.
South Korean President Lee Myung-bak greets President Obama during a welcome ceremony for the Nuclear Security Summit at the Coex Center, in Seoul, South Korea, on Monday.(AP Photo/Susan Walsh)
Obama and U.N. Secretary-General Ban Ki-moon talk at a working dinner hosted by South Korean President Lee Myung-bak at the Nuclear Security Summit.(AP Photo/Yonhap)
Obama talks with Crown Prince of Abu Dhabi Sheikh Abdullah bin Zayed Al Nahyan (right), as Georgian President Mikhail Saakashvili (left) and Australian Prime Minister Julia Gillard (second from left) listen before the leaders' dinner at the Nuclear Security Summit in Seoul.(AP Photo/Susan Walsh)
Obama talks with British Deputy Prime Minister Nick Clegg in Seoul.(AP Photo/Susan Walsh)
Obama converses with Indian Prime Minister Manmohan Singh.(AP Photo/Susan Walsh)
Obama and Russian President Dmitry Medvedev stand together at the end of a bilateral meeting at the Nuclear Security Summit in Seoul.(AP Photo/Pablo Martinez Monsivais)
Obama greets Chinese President Hu Jintao at the start of their bilateral meeting in Seoul.