About a dozen flights, including two from the United States, were diverted or canceled early Sunday after dark smog caused by a night of firecracker explosions obscured visibility at Manila’s airport, officials said.

Health Secretary Enrique Ona said the number of injuries — 454 from firecracker blasts and 18 from stray bullets — was slightly lower than last year but remained alarming.

Injured revelers, including many children, filled hospital emergency rooms in the capital shortly after midnight. Adding to the chaos, two gangs clashed in front of Manila’s main government hospital attending to the injured, leaving one man dead from a gunshot wound.

“Again, it seems our appeal to mothers to keep their children away from firecrackers wasn’t effective,” Ona told a news conference.

Many Filipinos, largely influenced by Chinese tradition, believe that noisy New Year’s celebrations drive away evil and misfortune. But they have carried that superstition to extremes, exploding huge firecrackers and firing guns to welcome the new year despite threats of arrest.

Interior Secretary Jesse Robredo said at least 65 people were arrested for using illegally large firecrackers.

Ona said he was willing to consider a proposal for a total ban on firecrackers but that it needed to be studied.

Dozens of hospitals nationwide went on full alert before midnight, their emergency rooms staffed with trauma doctors as if preparing for civil strife. Many people spent the night in hotels for added safety.

Health officials attempted to discourage dangerous celebrations by showing gory pictures of injuries, including hands mangled by firecracker blasts, and the national police chief threatened his men with dismissal if they fired their guns in revelry, but the violent tradition has continued.