Iranian students gathered for fresh pro- and anti-government rallies Sunday commemorating those killed in recent protests, as fears loomed of renewed conflict with the United States over the country’s nuclear program.The initial demonstrations were sparked in December by economic hardship in the sanctions-hit country, but quickly expanded into mass anti-government protests that marked one of the largest challenges to the Islamic Republic’s clerical leadership in years.For all the latest headlines follow our Google News channel online or via the app.US President Donald Trump had initially cheered on the protesters, threatening to intervene on their behalf as authorities launched a deadly crackdown, but his threats soon shifted to Iran’s nuclear program, which the West believes is aimed at developing atomic weapons.Washington and Tehran have since returned to the negotiating table, but Trump has simultaneously pursued a major military build-up in the Middle East aimed at pressuring Iran