The U.S. military will not allow troops to get within 80 kilometers ( 50 miles ) of the damaged plant . NEW : Japan and United States issue different early warning zones . Obama emphasizes that the U.S. is determined to do everything possible to support Japan . Kan briefs the president about how to contain the nuclear emergency at the Fukushima plant . He and Obama talk for about 30 minutes .
NEW : Japan and United States issue different early warning zones . Obama emphasizes that the U.S. is determined to do everything possible to support Japan . Kan briefs the president about how to contain the nuclear emergency at the Fukushima plant . He and Obama talk for about 30 minutes .