Barack Obama, the president of the United States, has tried to calm fears that the final pullout of troops from Iraq at the end of December 2011 will cause a dangerous power vacuum. <br /><br />In a joint press conference in Washington, Obama promised Nouri al Maliki, the Iraqi Prime Minister, that the United States would be a strong and enduring partner - and warned other nations not to interfere. <br /><br />Al Jazeera's Patty Culhane reports from Washington, DC, the US capital.
