MIAMI — At Miami International Airport, two large signs warn drivers of large vehicles not to pass beneath the 8-foot-6 inch concrete overpass. Authorities say two passengers are dead and others have been critically injured after a too-tall charter bus smashed into the overpass, crumpling metal.

One of the signs attached to the top of the concrete barrier reads: "High Vehicle STOP Turn Left." The other, placed to the left of the driveway and several feet in front of the barrier, says all vehicles higher than the 8-foot-6 threshold must turn left.

Authorities said the large, white bus carrying 32 members of a church group hit the overpass after the driver got lost Saturday, killing two male passengers and leaving three other passengers critically injured.

Airport spokesman Greg Chin said the bus was too tall for the entrance to the arrivals area and that buses are supposed to go through the departures area because of its higher clearance.

The bus was going about 20 mph when it struck the overpass Saturday morning, Chin added. News photographs showed the front of the vehicle's rooftop crumpled beneath the overpass.

Osvaldo Lopez, an officer with the Miami-Dade Aviation Department, said he heard a loud noise Saturday morning and rushed to help. He said he went inside the bus and found several passengers tossed into the center aisle. He said the passengers, many of whom were elderly, remained calm.

"It was just very bloody," he added.

Police said that one man, Serafin Castillo, 86, of Miami, died at the scene. A second man identified by authorities as Francisco Urana, 56, also of Miami, died later at a hospital.

Chin said passengers told him they were part of a group of Jehovah's Witnesses headed to West Palm Beach. Police said in a news release that the group had chartered the bus to take them to a church convention there.

The group was made up of congregation members of Sweetwater's Kingdom Hall of Jehovah's Witnesses, said Sweetwater Mayor Manny Maroño.

"This is a tragic accident that has affected many families, as well as, our Sweetwater family," Maroño said in a statement.

A phone number listed for the center in Sweetwater went unanswered in the hours after the crash.

Three people were at hospitals in critical condition. The other 27 surviving passengers were hurt, but their injuries were less extensive, authorities said.

Eight of the 14 patients initially taken to Ryder Trauma Center at Jackson Memorial Hospital were in stable condition while two others were in critical, said hospital spokeswoman Lidia Amoretti. Local reports said three people with lesser injuries were later released.

A majority of the injuries were facial due to the frontal impact, said Miami-Dade Police spokesman Det. Alvaro Zabaleta.

He said the driver was not familiar with the airport area and it was too early to say if charges would be filed. Investigators said they had conducted interviews Saturday with the driver, who suffered minor injuries.

"The preliminary info tells us that he wasn't too familiar with the area surrounding the airport, and that's what led him to take perhaps the wrong ramp that led him onto the property of the airport, and because of not being familiar with the airport, did not know or really see the height requirement in order for that bus to clear the overpass," Zabaleta said.

The bus was privately owned and typically used for tours, authorities said.

Markings on the bus show it was owned by Miami Bus Service Corp.

The company owns three motor coaches, according to the records. Miami Bus Service Corp. officials did not immediately respond to a phone message Saturday.

Federal Motor Carrier Safety Administration records found online show the company has had no violations for unsafe driving or controlled substances and alcohol. It also had not reported any crashes in the two years before Oct. 26, 2012.

The records show it did receive three citations related to driver fatigue in April 2011.