PALM VALLEY, Fla. -- Five people were killed and nine others transported to area hospitals after a boat hit a tugboat in the Intracoastal Waterway in St. Johns County early Sunday evening.

According to St. Johns County Fire-Rescue spokesman Jeremy Robshaw, a 22-foot boat with 14 people on board hit a 25-foot tugboat in the Intracoastal Waterway about one mile north of the Palm Valley Bridge just after 7 p.m.

All those injured were transported to Jacksonville-area hospitals. The three most seriously injured were transported by air ambulance.

The Florida Fish and Wildlife Conservation Commission said the tug was unoccupied and tied up to a barge at a work site where a dock and boat lift are under construction.

St. Johns County sheriff's deputies -- the first responders to the scene -- had to remove plywood from a partially completed house in the 100 block of Roscoe Boulevard to reach the end of the dock and begin rescuing victims.

The names and ages of the victims were not made available Sunday night. There was also no word on whether they were wearing life vests or how fast the boat was traveling.

The FWC, which was leading the investigation, questioned one witness and was seeking others. They said among their questions were why it appeared that 14 people were on a 22-foot boat and whether the owner was among those on board.

"You see tragedies occur from time to time, but this is a pretty significant thing," Robshaw told Channel 4.