A hospital official said a 23-year-old runner in Saturday's Baltimore marathon died after collapsing at the 25-mile mark.

Debra Schindler, a spokeswoman for Union Memorial Hospital, said the runner collapsed about 11:20 a.m. and was pronounced dead at the hospital about 1:10 p.m. Schindler said doctors were not able to revive the man, whose identity was not released.

The state’s medical examiner was expected to perform an autopsy Monday to determine the cause of death.

Event organizer Lee Corrigan told The Baltimore Sun, the runner fell near the last medical aid station where workers immediately came to his assistance. The station was one of seven along the route, which were staffed with 250 health care professionals, according to the report.

"We are heartbroken about it, and it puts a sad note on an otherwise great day for Baltimore," Corrigan told the newspaper. "Our hearts go out to him and his family."

Event organizers said the death was the second in the race's nine-year-history.

Click here to read more from The Baltimore Sun.

The Associated Press contributed to this report.