at a nuclear summit on friday, mr. obama said the republican presidential candidate doesn't know much about foreign policy or the world, for that matter. meanwhile, donald trump says he is not ruling out a third-party bid for the white house. it's not the first time the billionaire has said he's leaving the door open for an independent run. the front-runner says he wants to run as a republican but it depends upon how he is treated by the party's leaders at convention. >>> a construction company faces numerous charges, including attempted murder in connection with the collapse of an overpass in kolkata, india. at least 24 people died when a section of that bridge, which was under construction, crashed on thursday. an executive at the company denies any fault. >>> now to the migrant crisis in europe. police say that hundreds of migrants and refugees tore down part of a razor wire fence surrounding a building where they were being held on a greek island. they marched ten kilometers, that's about 6.2 miles, to a port to pr