Officials at the Philippine government disaster management agency told NBC News on Monday that nearly 22,000 people have already been evacuated.

But some residents could not move out of ash-blanketed villages due to a lack of transport and poor visibility, while others are refusing to leave their homes and farms.

The mayor of Taal, a town of about 60,000 people nine miles southwest of the volcano, said on the phone Monday their streets are covered in ash.

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Fulgencio Mercado, 62, said tens of thousands of residents have left by car, public transport or in vans and trucks arranged by the municipal government.

Residents near the volcano are evacuated on Monday. Eloisa Lopez / Reuters

But he estimates that about 10 percent of the population is still in the town, mostly people who are reluctant to leave their belongings, animals and homes.

"They should all leave," he said. "It's a mandatory evacuation."

Irene de Claro, a mother of four, worried about her father, who stayed in their village in Agoncillo town in Batangas while the rest of the family fled in panic.

“My father is missing. We don’t know too what happened to our house because the ash was up to our knees, it was very dark and the ground was constantly shaking when we left,” de Castro told The Associated Press in Batangas. “Most likely there’s nothing for us to return to. We’re back to zero.”

On Monday, flight operations partially resumed, but airport officials said they were closely monitoring the volcanic activity and could suspend operations at any time.

Government work and classes in schools in a wide swath of towns and cities were also suspended, including in Manila.

Taal had been restive for months until it suddenly rumbled back to life over the weekend, blasting steam, ash and pebbles up to nine miles into the sky, according to the Philippine Institute of Volcanology and Seismology.