Mahmoud Ahmadinejad, Iran's president, has condemned a nuclear security summit in the US, where international leaders are meeting to work out a global nuclear security strategy.

Representatives from 47 nations gathered in Washington, DC on Monday for the start of the two-day summit hosted by Barack Obama, the US president.

Obama began the gathering with a series of bilateral meetings with some of the world leaders gathered for the summit.

But Ahmadinejad, whose country was not invited to attend the conference, called the meeting "humiliating to humanity".