SHANGHAI (AP) — Protesters angered by strict anti-virus measures have called for China’s powerful leader to resign. That’s an unprecedented rebuke. It came as authorities in at least eight cities struggled to suppress demonstrations Sunday that represent a rare direct challenge to the ruling Communist Party. Police using pepper spray drove away demonstrators in Shanghai who called for Xi Jinping to step down and an end to one-party rule. Hours later, people rallied again in the same spot. Police again broke up the demonstration, and a reporter saw protesters under arrest being driven away in a bus. The protests began Friday and have spread to cities including the capital, Beijing, and dozens of university campuses. They are the most widespread show of opposition to the ruling party in decades.