U.S. Democratic presidential candidate Hillary Clinton on Monday said removing Bashar al-Assad is the top priority in Syria.Clinton, speaking at a town hall meeting in Hollis, New Hampshire, said the United States should pursue a diplomatic solution in resolving Syria's internal conflict.In a separate speech in Manchester, Clinton unveiled new gun control measures aimed at strengthening background checks on gun buyers and eliminating legal immunity for sellers, days after a deadly shooting in Oregon.Clinton has made strengthening gun laws a centerpiece of her presidential campaign, vowing she would use her executive power as president to expand background checks for sellers at gun shows and online and back legislation banning domestic abusers from purchasing guns.Clinton proposed a repeal of legislation that shields gun manufacturers, distributors and dealers from most liability suits, even in the case of mass shootings like the one that killed nine people at a community college on Thursday.She also backed congressional efforts to stop retailers from selling guns to people with incomplete background checks, as happened when Dylann Roof, the man charged in the Charleston church shooting, bought his gun."I will try every way I can to get those guns out of the hands of people who shouldn't have them," she said. "We need to prevent these kinds of terrible crimes that are happening."The plan marks an effort by Clinton to stake out liberal ground against her closest rival, Vermont Sen. Bernie Sanders. While Sanders has wooed the Democratic base with his liberal positions on issues like income inequality and college debt, he's struggled to defend a more mixed record on gun legislation a reflection, he says, of his rural, gun-friendly home-state.Clinton has emerged as one of the fiercest proponents of tougher gun control after a series of shootings over the past several months has reignited debate over gun laws in the presidential campaign.