A nine-story building under construction in Angeles City collapsed before dawn on Sunday, leaving at least 21 people missing, according to Philippine authorities.

Officials said 24 workers either escaped on their own or were rescued from the wreckage. Rescue teams reported hearing voices beneath the debris, raising hopes that more survivors could still be trapped alive.

The incident occurred following a severe thunderstorm that struck the city in Pampanga, north of Manila. More than 100 police officers and emergency responders were deployed to search the unstable rubble, said police Brig. Gen. Jess Mendez.

Authorities confirmed there were no immediate reports of fatalities, although several survivors suffered injuries. Most of the 21 missing individuals are believed to be construction workers, according to Francis Pangilinan.

Two additional people, including a Malaysian tourist, were hurt after debris from the collapsed structure struck nearby accommodations.

Rescue personnel, including firefighters, police, and disaster-response teams, continued combing through the debris using sniffer dogs and manual search efforts. Public Works Secretary Vinzon Dizon said rescuers were proceeding carefully because of the unstable condition of the site.

“There are signs of life, and voices can still be heard,” Dizon told reporters, stressing that the top priority was to safely rescue those trapped.

Angeles City, once home to one of the largest U.S. Air Force bases outside the United States, developed into a major commercial and entertainment center after the base’s closure in the early 1990s. The former military facility is now known as the Clark Freeport Zone, located around 80 kilometers north of Metro Manila.