Hong Kong police used tear gas and pepper spray to try to disperse thousands of protesters challenging Beijing’s decision to restrict democratic reforms in the Asian financial hub. The clashes raised the stakes in the face-off against Chinese President Xi Jinping’s government, which has taken a hard line against threats to the Communist Party’s rule.

With little warning, Mount Ontake in Japan’s Nagano prefecture erupted on a sunny autumn Saturday — the perfect day for a hike — sending a plume of gas and ash skyward. At least 31 people are believed to have died from unclear reasons — possibly from toxic gases, suffocating ash or falling rocks.