MANILA — A powerful earthquake shook the northern Philippines on Monday, leaving at least 11 people dead in collapsed buildings, municipal and disaster relief officials said.

The Philippine Institute of Volcanology and Seismology said the quake had registered a magnitude of 6.1 and had been centered near the town of Castillejos in Zambales Province, west of Manila. It struck shortly after 5 p.m., as government offices and private businesses were closing for the day.

In the town of Porac, northwest of Manila, five people were reported crushed to death after a wall in a four-story supermarket collapsed, RJ Mago, a spokesman for the National Disaster Risk Reduction and Management Council, told a local radio station.

[One day after the deadly tremor, a powerful earthquake struck Samar, an island in the central eastern Philippines.]