GILA BEND, Ariz. >> Two Border Patrol agents rushing to help capture some suspected illegal immigrants were killed Thursday when their SUV entered a marked railroad crossing and was struck by a freight train.

The crash happened at about 6 a.m. MST in a rural farming area near Interstate 8 and the town of Gila Bend, about 85 miles southwest of Phoenix.

The agents — Eduardo Rojas Jr. and Hector Clark — were trying to position themselves on a road north of some other agents who were trying to capture a group of suspected illegal immigrants, said agent Kenneth Quillin, spokesman for the Border Patrol’s Yuma sector.

The suspects were on foot, and none of them have been arrested, Quillin said. “We do see groups (of illegal immigrants) on a regular basis traveling through this area.”

The railroad crossing where the wreck occurred is marked but does not have railroad crossing arms, he said.

The Union Pacific train with 75 cars was westbound after leaving Phoenix. It was going about 62 mph when it hit the SUV, pushing it about a half-mile down the tracks.

Before the collision, the train engineers spotted the SUV on the access road and “sounded a horn a quarter-mile” before the crossing, Maricopa County Sheriff Joe Arpaio said at an afternoon news conference.

Union Pacific said in a statement its crew had no warning that the SUV would turn in front of the train. It did not elaborate.

Arpaio declined to speculate on what might have caused the fatal accident.

“We are all at risk in that area of enforcing the drug and illegal immigration law,” he said. The sheriff’s office and FBI are investigating the deaths.

Hours after the crash, the mangled black SUV sat on the tracks in front of the train’s engine as several agents and other law enforcement officers combed the area. Tarps were placed over some of the wreckage.

There have been six previous accidents at the privately owned railroad crossing, dating back to 1984, but only one involved a fatality, records show. One person died in July 2003 when a semi-truck driver failed to make a complete stop and was struck by a train.

Rojas and Clark were assigned to the Yuma sector, which has close to 1,000 agents.

Clark, who was 39 years old and a native of Yuma, had been an agent since August 2001. The 35-year-old Rojas was originally from El Paso, Texas, and had been an agent since April 2000.

Each agent is survived by a wife and two children.

“It’s sad anytime you lose somebody in our organization,” said George McCubbin, president of the National Border Patrol Council.

Homeland Security Secretary Janet Napolitano issued a statement saying, “The entire DHS family expresses our deepest sympathies to the family and friends of these agents.”

Arizona Attorney General Tom Horne said he joins all Arizonans in mourning the deaths.

“This tragedy is a reminder to all of us that whether they are facing down a criminal suspect with a weapon, or patrolling the highways and deserts, these law enforcement professionals encounter life-threatening dangers every day,” Horne said in a statement.