Two people were found dead in their home Sunday after a large “three-alarm” fire broke out at a two-story apartment building in Waikiki.

The Honolulu Fire Department received a 911 call at 3:02 p.m. for the fire at 1829 Kaioo Drive. HFD sent 13 units staffed with about 51 personnel with the first unit arriving at 3:08 p.m. The building was engulfed in smoke and flames, HFD said.

Firefighters brought the fire under control at 3:26 p.m. and extinguished it at 3:42 p.m.

“Due to concerns of the structure’s integrity, a search for occupants commenced after the fire was extinguished and rescue personnel could confirm entry into the affected units was safe,” according to an email from HFD.

Two people were found dead in their home, but their identities were not immediately released. Emergency Medical Services treated and transported two people in serious condition to the hospital.

An investigation has been ordered to determine the fire’s origin and cause along with damage estimates.

The American Red Cross was contacted to assist with any displaced occupants.