The death toll in an explosion at a residential community in Baoding, Hebei province, rose to three on Sunday, as the authorities launched a citywide search for illegal explosives.

The blast ripped through an apartment block in the city's Yaoheningyuan residential community at about 3 pm on Saturday, initially killing one person.

Rescue teams found two more bodies on Sunday morning, while another 30 people are still in hospital. Two are in a critical condition and three are severely injured, said Yin Xiaolong, a spokesman for the city government.

Police searching the basement of the building found homemade detonators and materials used in the manufacturing of explosives.

The discovery has led the authorities to the initial conclusion that the blast was the result of the unlicensed manufacturing and storage of explosives, Yin said, adding that the investigation was continuing.

In a video news conference on Saturday night, Baoding authorities said a citywide check of explosives has been launched, and residents are encouraged to report the illegal manufacturing of explosives to the police.

Four residential buildings near the scene of the explosion have been cordoned off since Saturday afternoon, and their residents are being accommodated in hotels, according to the authorities.

The blast was so strong that many people nearby said they initially thought it was an earthquake.

"My first reaction was that it was an earthquake and that I should run outside of my office," said Liu Congchao, 22, whose workplace was only 200 meters from the scene of the blast.

He ran outside and found the residential area opposite his office building shrouded in dust and smoke. Liu said shattered glass was everywhere, while cars parked nearby were also damaged.

The blast occurred in the middle of the eight-day national holiday. The timing may have prevented more injuries and deaths.

"Many residents were out of town for the holidays," said Liu Xihuan, a 22-year-old university student who lives near Yaoheningyuan. "I could not imagine the blast occurring at another time."

Contact the writer at xuwei@chinadaily.com.cn.