Monday's top 5 headlines: What you need to know

The Weeknd wins big at the 2016 Billboard Music Awards — The 26-year-old won eight honors, including Top Hot 100 Artist and Top RnB Artist. President Obama will not apologize for Hiroshima — Obama reiterated he would not apologize for the devastating attack during his visit over the weekend. The U.S. ended an arms embargo on Vietnam — China hopes for "normal and friendly" relations between the U.S. and Vietnam are conducive to regional stability. Baltimore police officer Edward Nero not charged in Freddie Gray's death — Nero, 30, was initially charged with second-degree assault, reckless endangerment and two counts of misconduct in office. U.K.'s David Cameron warns leaving EU could be self-destructive — Leaving the EU would be the "self-destruct option" for Britain and could cost the country as many as 820,000 jobs, Cameron is warning.