WASHINGTON - President Barack Obama on Monday renewed his commitment to a "new beginning" with the Muslim world, vowing no let-up in US efforts to promote Middle East peace, curb militant violence and boost economic development. Seeking to build on his outreach to Muslims in a speech in Cairo last June, Obama used a US-hosted Muslim business conference to underscore what his administration has done so far and to pledge further work to overcome mistrust. While Obama has made progress towards mending America's image in the Islamic world, he still faces stiff challenges in his handling of the stalled Israeli-Palestinian peace process, the nuclear standoff with Iran and wars in Iraq and Afghanistan. "I knew that this vision would not be fulfilled in a single year, or even several. But I knew we had to begin and that all of us have responsibilities to fulfill," Obama told the Presidential Summit on Entrepreneurship. The focus on business development marked the Obama administration's strategy of trying to broaden the conversation with Muslims beyond the "war on terrorism" that dominated the Bush-era approach and alienated many.