CHICAGO (Reuters) - Two Chicago police officers were struck and killed by a passing commuter train on Monday while investigating a report of gunfire near railroad tracks on the city’s Far South Side, police said.

The two officers, Eduardo Marmolejo, 37, and Conrad Gary, 31, both assigned to the Chicago Police Department’s Calumet District, were pursuing a suspect along the Metra railway line when they were killed, police said.

City police Superintendent Eddie Johnson told a news conference there was no rail stop at the location where the officers were struck, and the train was probably traveling at 60 to 70 miles per hour at the time.

The individual the policemen were pursuing was ultimately arrested, and a weapon was recovered, police said.

The officers’ deaths were especially devastating as they followed several other tragedies in the Calumet District this year, including two recent officer suicides, Johnson said.

Both Marmolejo, who had served on the department for 2-1/2 years, and Gary, who joined 18 months ago, were the fathers of young children, he said.

Joining the superintendent at a late-night news conference hours after the fatal train accident, a somber Mayor Rahm Emanuel said: “There are no words that can express the grief, the sense of loss. It just knocks you back on your heels.”

“It’s really important to put our arms around the Chicago Police Department and hold them up at this critical juncture,” Emanuel said.

The deaths occurred during the evening rush-hour. The Chicago Tribune reported that Metro officials shut down all service on the Metra Electric District tracks Monday evening while authorities worked at the scene of the accident.