YANGON, Myanmar — A strong 6.8-magnitude earthquake struck northern Myanmar on Sunday, collapsing a bridge and a gold mine, damaging several old Buddhist pagodas, and leaving as many as 12 people feared dead.

A slow release of official information left the actual extent of the damage unclear after Sunday morning’s strong quake. Myanmar has a poor official disaster-response system, despite having lost upward of 140,000 people to a devastating cyclone in 2008.