US President Barack Obama has accepted his Nobel Peace Prize at a ceremony in Norway’s capital, Oslo.
In his acceptance speech, he said his accomplishments were slight compared with some previous laureates.
He defended the US role in Afghanistan, saying sometimes war was necessary, but a just war could lead to a just peace.
Mr Obama was given the prize in October for his “extraordinary efforts to strengthen international diplomacy and co-operation between peoples”.
The ceremony came days after Mr Obama announced he was sending 30,000 extra US soldiers to the war in Afghanistan.
There was a mixed reaction when he was named as the winner of the prize for 2009.