The UN Security Council has approved a fourth round of sanctions against Iran over its nuclear programme.

Having pushed hard for punitive action, Barack Obama, the US president, stressed that "the door on diplomacy" had not shut.

Mahmoud Ahmadinejad, Iran's president, said the sanctions were "valueless" and incapable of hurting his people.

Al Jazeera's Kristin Saloomey reports from the United Nations.

Source: Al Jazeera