MOSCOW (AP) — Russian President Vladimir Putin scoffed Thursday at allegations of collusion between U.S. President Donald Trump's campaign and Russia, saying the reports have been "invented" by Trump's foes and have hurt the U.S. political system. He also mocked his most visible critic, Alexei Navalny, who is barred from challenging Putin in the March 18 presidential vote due to an embezzlement conviction, saying those like him want to plunge Russia into a destabilized quagmire. He vowed not to let that happen.