An Amtrak train en route from New York to Miami collided with a CSX freight train and derailed near Columbia, South Carolina, leaving two dead and 116 injured, police and Amtrak officials said.

The crash occurred at 2:35 a.m. in Cayce, South Carolina, causing the lead engine and “some passenger cars” to derail, Amtrak said. There were eight crew members and about 139 passengers, Amtrak said.

The two people killed were Amtrak employees, according to South Carolina Gov. Henry McMaster. The CSX freight train was empty, he said. Amtrak confirmed the two fatalities were its employees.

The Lexington County coroner identified the victims as the train’s engineer, Michael Kempf, 54, of Savannah, Georgia, and conductor Michael Cella, 36, of Orange Park, Florida.

Derrec Becker of the South Carolina Emergency Management Division said injuries reported include minor cuts as well as broken bones, and he said all passengers had been removed from the train. Lexington County spokesman Harrison Cahill said passengers who were hurt were taken to local hospitals, but none had life-threatening injuries.

There were two leaks from the train, spilling an estimated 5,000 gallons of fuel, but there was “no threat to the public at this time,” Cahill said at a news conference. The cause of the crash is not known. He later said that it was unclear from where the fuel had leaked.

The National Transportation Safety Board and Federal Railroad Administration are both at the site to investigate the crash.

“The Federal Railroad Administration Investigative team is on site to support to the National Transportation Safety Board’s investigation,” the U.S. Department of Transportation said in a statement. “We are closely monitoring the situation and have been in contact with CSX and Amtrak as well as federal, state and local officials.”

The Transportation Department said Secretary Elaine Chao also is sending her senior adviser, Jim Ray, to the crash site. “It is important to understand the factors that contributed to this tragic accident and how all stakeholders can ensure a safe and reliable rail system going forward.”

Amtrak said it was “cooperating fully” with the NTSB investigation.

In a statement, Amtrak said CSX owns and controls the Columbia Subdivision tracks where the crash occurred, including overseeing the dispatching of trains and signal systems. CSX’s duties include “directing the signal systems which control the access to sidings and yards,” Amtrak said.

President Trump offered his words of support and thanked first responders in a tweet Sunday morning: “My thoughts and prayers are with all of the victims involved in this mornings train collision in South Carolina. Thank you to our incredible First Responders for the work they’ve done!”

This is the third crash involving an Amtrak train in less than three months. Last week, an Amtrak train carrying Republican lawmakers to a retreat in West Virginia collided with a garbage truck. One person in the truck was killed in the crash in Crozet, Virginia. In December, an Amtrak train in Washington state derailed while crossing an overpass, spilling cars onto a busy highway and killing three people.

Federal investigators have not determined the cause of the earlier crashes; investigations can take months or even years, but the incidents are likely to raise concerns about the safety of the nation’s rail system and focus more attention on the push to install a technology known as positive train control, an automatic braking system that federal safety officials say could have prevented hundreds of deaths and thousands of injuries over the years. Last month, Chao told railroad industry officials that they are expected to meet the deadline to have the systems installed by the end of this year.