At least ten people have been killed and approximately 90 injured, according to news reports.
Officials have recovered two of the trains' three black boxes
During a press conference, German authorities said they hoped the recovery of the trains' black boxes would shed light on what led to the accident. In the meantime, authorities declined to speculate on what caused the crash.
"The two trains must have approached each other at a high speed and they must have had a head-on collision at high speed," German Transport Minister Alexander Dobrindt said.
The crash happened in the stretch of a curve in an area with a speed limit of roughly 60 mph, according to officials.
"One had to assume the two train drivers had little, if any, visual contact with each other," Dobrindt said. "It is to be assumed the accident happened without any braking maneuver beforehand."
All survivors transported from the scene
Roughly five hours after the trains collided police told The Associated Press all survivors had been transported from the scene to hospitals.
Federal police spokesman Rainer Scharf told the wire service officials will shift their focus to what caused the accident.
Rescue efforts hampered by confusion
Police spokesman Stefan Sonntag told The Associated Press the scene of the accident was "so confusing" it was difficult to immediately say how many people were injured or killed in the crash.
According to German media reports, rescue efforts were initially hampered by the several carriage cars turned over in the collision and the remote location of the crash.
Accident the region's largest in recent memory
Area officials said the collision, which happened around 7 a.m. local time, was unprecedented in recent memory.
"This is the biggest accident we have had in years in this region and we have many emergency doctors, ambulances and helicopters on the scene," police spokesman Stefan Sonntag told The Associated Press. "We have a lot, a lot of staff on the ground who are all involved in the rescue efforts."
Both trains partially derailed by collision
"One train really drilled itself into the second train and the driver cab of the second train has been entirely shattered," Dobrindt said.
According to Bayerische Oberlandbahn, the company which runs the train lines that collided Tuesday, the impact of the crash partially derailed both trains and wedged their cars into one another.
"The accident is a huge shock to us," said Bernd Rosebusch, managing director of Bayerische Oberlandbahn. "We are doing everything we can to help the travelers, families and employees."
Helicopters, boats aid emergency response teams
The heavily forested area where the accident took place was flooded with emergency responders shortly after reports of the accident went out, according to officials.
Dobrindt said firefighters arrived on scene just three minutes after the first alarm was sounded. In all, authorities estimated 500 emergency responders helped search for survivors and injured passengers. In addition, 15 helicopters were used in the search.
"They really mobilized all the technical equipment, including helicopters," said Bavarian Minister of the Interior Joachim Hermann. "That makes the optimal rescue mission possible ... It was done very professionally."