KAPRUN, Austria (AP) _ Authorities began telling grieving relatives the names of the dead Sunday, a day after flames engulfed a cable car traveling through an Alpine tunnel and killed about 170 skiers and snowboarders.

The cable car’s passengers tried to flee the deep tunnel during Saturday’s blaze, but most were felled by the thick smoke and raging fire. On Sunday, chief firefighter Anton Brandauer said retrieval of the bodies _ many of them children or teen-agers _ could begin since the tunnel was now almost smoke-free.

The retrieval had been delayed by toxic fumes and the need to secure the charred car.

Authorities have identified 155 of the people killed with 90 percent certainty, Salzburg Gov. Franz Schausberger told reporters Sunday. Of those, there were 52 Austrians, 42 Germans, 17 Japanese, eight Americans, two Slovenes and one Croat, he said. Authorities have not yet established the nationalities of the remaining 33 people.

The identities apparently were established by eliminating those who had returned from a list of 2,500 people who had taken the cable car up to the glacier ski slope. Authorities had not yet released victims’ names to the press.

Three U.S. army personnel were confirmed among the dead. The Americans were part of a group of mostly military personnel from Wuerzburg, Germany, and their families, said Maj. Drew Stathis, a member of the group.

Stathis said the missing Americans included a family of four with two children, an engaged couple and a man and his son.

It was still unclear exactly how many people were on board the cable car, and authorities have not established the cause of the fire.

Psychiatrist Thomas Kamolz, who talked to survivors, spoke of dramatic scenes inside the cable car after the fire broke out, with one person breaking a window with his ski pole and a survivor claiming to have seen “a father throwing out his child in order to save it.”

The fire may have started before the car entered the tunnel, Austrian public security chief Erik Buxbaum said Sunday.

“We have received information that the light of a fire was already visible to outside witnesses as the train was entering the tunnel,” Buxbaum said.

But when the driver noticed the blaze it was already too late, he said. Other officials later said it appeared the fire broke out at the rear end of the cable car.

Buxbaum said he could not yet comment on rumors that the train was carrying diesel fuel or fireworks or that a bomb had been planted aboard.

Most of the victims apparently managed to escape from the car but were killed by fumes while running up narrow stairs leading out of the tunnel, Manfred Mueller, the cable car’s head technician, told reporters. The survivors apparently ran the opposite way, avoiding most of the smoke being blown upward through the tunnel by strong drafts.

Authorities told reporters that fresh air sucked into the tunnel fed the flames. The blaze “spread at a raging speed _ like in a chimney,” Schausberger said.

The 18 survivors apparently included 12 who escaped from the car and six waiting at the top of the tunnel. One survivor was in serious condition with lung injuries from breathing in noxious fumes. Two more remained hospitalized, but the others were released.

Speaking to the Austria Press Agency, an unidentified survivor said the crowd trapped inside the compartment “screamed … and tried desperately to find a way out.”

“My only thought was to get out, and I could save myself in the last second because a window was kicked in and I could fight my way outside,” the survivor said.

Schausberger said a majority of those killed were “undoubtedly young people.” Also among the dead were 32 people from the Upper Austrian city of Wels, including 13 municipal employees.

The Austria Press Agency described the disaster as the worst accident involving skiers transported by a cable-pulled car to slopes, surpassing the death toll at the Italian ski resort of Cavalese in 1976, when 42 people died after a suspension cable snapped.

The cable car, pulled on rails underground for most of its more than 3,200-yard path up the Kitzsteinhorn mountain to the glacier region, burned after having traveled about 600 yards inside the mountain in the heart of the Austrian Alps.

The fire started Saturday morning, but rescuers were unable to reach the compartment where the blaze broke out until after nightfall. Those who ventured inside said the car was burned down to the chassis.

Schausberger said he was at a loss to explain what happened. Everything was fine when inspectors from the Transport Ministry checked the cable car system in September, he told reporters.

The cable car caught fire at a time when thousands of people were enjoying late fall sunshine and balmy temperatures on the slopes in the heart of the Austrian Alps, on the opening day of the region’s ski season.

Built in 1974, the cable railway was one of the first of its kind with a tunnel passing through a mountainside.

–MELISSA EDDY