TOHOKU, Mexico -- Sixteen Seattle-area tourists -- fans of the University of Washington football team -- on a Caribbean cruise died during a side trip to visit Mayan ruins when their plane crashed in the eastern Mexican state of Yucatan. Three Mexican crew members also died.

Soldiers barred access to the accident site, but digital photographs showed the tail was the only surviving piece of the twin-engine LET 410 turboprop plane, which crashed Wednesday night.

The tourists were on a cruise aboard the Maasdam for University of Washington football fans who planned to attend Saturday's game against the University of Miami in the Orange Bowl, according to cruise operator Holland America Line. The game was postponed because of Tuesday's terror attacks.

"I was shocked to hear of this tragedy," said UW athletics director Barbara Hedges, in a statement posted on the university's web site. "Obviously, our prayers and thoughts go out to the families of those who perished in this terrible accident. I know that everyone in the Husky family wishes to express their deepest sympathy to those involved. This has obviously touched the lives of people associated with Washington athletics. This is just terrible news."

Former UW football coach Don James and famed Huskies quarterback Sonny Sixkiller were on the cruise, but did not take the side trip and were not aboard the plane that crashed, according to Casey Sixkiller, the former coach's son. The younger Sixkiller called KING television in Seattle to tell them his father and James were safe.

"This is a terrible tragedy for the loved ones and friends and our entire community," said A. Kirk Lanterman, the line's chairman.

A federal civil aeronautic official, Andres Perez Zentella, said the crash was an accident and discounted any connection to the terrorist hijackings of four jetliners in the United States on Tuesday. He did not release any other information about the crash.

The Maasdam had left Ft. Lauderdale, Fla., on Sept. 9 with 1,151 passengers and had stopped at Grand Cayman island before arriving Wednesday morning in Cozumel, a Caribbean island off the coast of the Yucatan Peninsula famed for its coral reefs.

Among the victims were Oak Harbor, Wash., residents Dwight Mitchell, a former city council member, and his wife, Lois, and Theodore Zylstra, a prominent attorney. Geoffrey Vernon, 59, a Seattle University regent, and his wife, Judy, were among those killed.

The others killed in the crash, all Washington state residents, were Karen O. Burks (Seattle), Scott D. Columbia (Renton), Charles A. Genther (Seattle), Shirley M. Genther (Seattle), Mary E. Kearney (Oak Harbor), Barbara E. Martin (Lake Forest Park), Larry L. Schwab and Linda S. Schwab (Seattle), Lisa M. Styer (Seattle), and Larry R. Wade and Judy A. Wade (Seattle).

The 16 tourists boarded a twin-engine LET 410 turboprop at midday and flew without incident to the Mayan ruins at Chichen Itza, according to Fernando Vargas, director general of the Aero Ferinco airline.

They took off for the 40-minute return trip under a clear, sunny sky at about 5 p.m.

"There were no indications of an emergency," Vargas said.

An eyewitness to the crash, Fausto Cob Batun, said he and about 50 others were at a nearby school when they saw the plane approach.

Cob said the plane was tilted at an angle and one of its propellers wasn't working. It crashed into a field, exploding when it hit the ground, he said.

"The firefighters came about 15 minutes later but they couldn't do anything because they couldn't get in," Cob said. "They had to haul buckets of water in because their hoses wouldn't reach."

Vargas said the plane was flying at about 500 feet when it began turning onto a course requested by the air traffic controller. "It did not stop turning" and suddenly plunged to the ground, he said.

He said Mexican federal aviation officials were investigating.

Vargas said the pilot, Jose Luis Romero, had 7,100 hours flying time and co-pilot Aurelio Perez Escalante more than 1,000.

State police in the city of Valladolid, near the crash site, said the bodies had been recovered and were being returned to the state capital, Merida, for autopsies.

Information from KING5.com was used in this report.