Leaders in Washington for nuclear security summit

Kazakh President Nursultan Nazarbayev (C) arrives at Andrews Air Force Base, Maryland April 10, 2010. Nazarbayev will participate in the nuclear security summit in Washington called by US President Barack Obama. [Photo/Agencies]  

U.S. President Barack Obama (R) meets with Kazakh President Nursultan Nazarbayev at Blair House in Washington April 11, 2010. Nazarbayev is in town for this week's nuclear security summit. [Photo/Agencies]