On the eve of a summit of the world's 20 top economies, the Obama administration pressed leaders at the UN to overcome differences and work together more closely in confronting thorny financial and environmental problems.<br /><br />Barack Obama, the US president, delivering his first speech to the UN General Assembly in New York on Wednesday, urged world leaders to join him in confronting an abundance of global challenges.<br /><br />Leaders gathering in Pittsburgh, Pennsylvania, face daunting challenges in overcoming differences on major issues ranging from restraining bankers' bonuses to overhauling financial regulation and plotting a future course for sustainable growth as the worst of the downturn appears to be over.<br /><br />Several groups plan to stage protests in Pittsburgh during the two-day summit, with the main event being a march on Friday, in which thousands are expected to take part.<br /><br />The talks are expected to focus on ways of regulating the global financial market to prevent another economic collapse.<br /><br />But as Al Jazeera's Rob Reynolds reports, many nations remain divided on the best way to do this.
