Washington, Sha'ban 26, 1437, June 02, 2016, SPA -- The US should not retreat from the world stage, US President Barack Obama warns amid calls by Republican candidate Donald Trump to put America first, according to dpa. "America cannot shirk the mantle of leadership," Obama says during a graduation speech at the US Air Force Academy in Colorado. "We can't be isolationist, it's not possible in this global, interconnected world." Obama defended his foreign policy legacy, including his decision not to use military strikes against Syria over its use of chemical weapons, stressing the use of military force should always be a last resort. The US will remain committed to seeking a diplomatic solution in Syria, rather than risk becoming stuck in a "quagmire" by becoming directly involved in the civil war like Russia and Iran, he says. --SPA 22:35 LOCAL TIME 19:35 GMT www.spa.gov.sa/w