CHICAGO (AP) -- Officials say 40,230 runners participated in the Chicago Marathon -- with that many at least starting the race Sunday. Officials say they don't know yet how many finished, but the number of participants sets a Chicago Marathon record.
Dr. George Chiampas of Northwestern Medicine is leading the race's medical team. He says about 750 people have needed medical attention so far and 26 were transported to hospitals. He says none of them seemed to be in critical condition.
Security was heightened for the first major marathon in the United States since the Boston Marathon bombings in April.
Chicago police say no problems have been reported.
Runners from more than 120 countries and all 50 states observed a moment of silence for the Boston victims and families before the race began.