A fire swept through a condominium building in central Missouri town Osage Beach on Tuesday, leaving four children - ages two to five - dead, fire officials revealed on Wednesday.

"We've had fire loss before, and many types of tragedies, but to lose four children under the age of 5 in one call is something my staff will struggle with," said Jeff Dorhauer, the Osage Beach Fire Chief, according to Reuters.

Investigators are treating the fire as suspicious until they know otherwise. However, the police chief and fire chief said on Wednesday morning that it is not an indication that emergency responders believe the fire was something criminal.

Firefighters said that the children were cousins and lived in the lake area, while the police revealed that they were celebrating a birthday, but did not know whose it was.

The fire department received a call late Tuesday evening at around 11:30 p.m. and the firefighters found the fourth floor unit of the Compass Pointe condominium engulfed in flames and six people trapped inside once they arrived on the scene, KY3 reported.

"We were able to knock the fire down quickly enough to get inside and make a recovery on the children but none of the four did make it," said Dorhauer.

It took 60 firefighters to put out the blaze. The children were then taken to a local hospital, where they were pronounced dead, according to NBC News.