MANILA (2nd UPDATE) - Sixteen people died in Pampanga and Zambales due to a powerful quake that rattled Luzon, a local disaster official said Tuesday, as search and rescue operations in toppled structures continued.

The magnitude 6.1 quake on Monday afternoon centered in neighboring Castillejos, Zambales and was felt in Metro Manila and other areas, where it caused buildings to sway and drove terrified residents and office workers to the streets.

BREAKING: Death toll in 6.1-magnitude #LuzonQuake rises to 16, NDRRMC Usec. Ricardo Jalad says. #ANCRecap pic.twitter.com/Mq9J8QBRjA

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"Death toll as of now in Region 3 is 16, most of these are coming from Porac, Pampanga with 12 and there are other areas with casualties like Lubao, Angeles City and Zambales," National Disaster Risk Reduction and Management Council Executive Director Ricardo Jalad told ANC.

Pampanga has been placed under a state of calamity following the quake.

Eight people died in Porac, including five from a collapsed supermarket. Among those who perished in the supermarket was a woman and her two young children.

Nine people have been pulled out alive from the rubble as of Tuesday.

Rescuers continue searching for survivors from the collapsed establishment.

In Angeles City, a 74-year-old woman died after an alley wall collapsed on her in Barangay San Jose.

In Lubao, a 56-year-old woman and her 6-year-old granddaughter were crushed to death when a wall gave in while they were fleeing to an open space.

Another 6-year-old fatality was reportedly crushed to death by falling rocks in San Marcelino, Zambales.

Phivolcs chief Renato Solidum explained that the quake caused more damage in Pampanga than in its Zambales epicenter because the ground is softer in the former.

"Kung titingnan natin ang kondisyon ng kalupaan diyan sa Pampanga, ito po ay karamihan ay lahar na malambot po 'yan. Ang Subic town at Olongapo proper ay nasa floodplain, malambot din po 'yan. Kahit malayo po ito kumpara sa Castillejos, ang Castillejos ay matigas ang foundation," he told radio DZMM.

(If you look at the condition of the ground in Pampanga, most of it is lahar, which is soft. Subic town in Olongapo proper is in a floodplain, the soil is also soft there. Even if Castillejos is farther, it has solid foundation.)

He added that he does not fear any major aftershocks would affect Metro Manila.

"Ang Bohol [quake] ay magnitude 7.2. Major earthquake talaga 'yun... Itong nangyari na magnitude 6.1, hindi 'yan major earthquake. Nasa borderline siya ng strong earthquake. Napakalayo na ng Metro Manila para maramdaman ang aftershock. Kaya nung ako'y tinanong kung puwede na magsibalikan ang mga tao, puwede namang bumalik basta nagkaroon ng visual inspection. Sa Phivolcs, continuous ang operation namin," he said.

He was referring to the deadly 2013 Visayas quake that devastated several provinces in central Philippines.

• Death toll due to Bohol quake rises to 215

(The Bohol quake was a magnitude 7.2. That was a major earthquake. What happened (in Pampanga) was magnitude 6.1, that was not a major earthquake. It was on the borderline of a strong quake. Metro Manila is very far to experience aftershocks. That's why when I was asked if people can go back, it's ok if there was visual inspection. We in Phivolcs continue our operations.)

Meanwhile, Jalad told DZMM that four structures sustained the most damage, including a bridge in Floridablanca, Pampanga which the Department of Public Works and Highways already declared closed, a church in Lubao and the Clark International Airport in the same province, and the Emilio Aguinaldo College in Metro Manila.

"Clark International Airport nag-sustain din ng damage resulting [in] closure for 24-hours lang naman. Hopefully mag-resume na 'yan ng operations within the day," said Jalad.

(The Clark International Airport sustained damage resulting in its closure only for 24 hours. Hopefully it can resume operations within the day.)

Jalad also said they received about 29 reports of damaged structures.

"Pero karamihan doon ay minor, not resulting [in] casualties or injuries," he said.

(But most of that are minor, not resulting in casualties or injuries.)

The Philippines is part of the Pacific "Ring of Fire", an arc of intense seismic activity that stretches from quake-prone Japan through Southeast Asia and across the Pacific basin. - With a report from Joyce Balancio, ABS-CBN News; Agence France-Presse