COLUMBUS —Expect security to be somewhat tightened as you enter Ohio Stadium — or even drive near it — for the 3:30 p.m. kickoff when Ohio State hosts Illinois on Saturday.

Federal bulletins sent to police departments this week and obtained by The Associated Press said officials knew of no specific plots against stadiums and other entertainment venues, but cautioned officers and private companies to be vigilant.

Similar alerts often are issued — a recent one focused on the vulnerabilities of mass transit systems — but they’ve received increased attention in the last week against the backdrop of ongoing terror investigations in New York City and Denver.

Michigan Stadium officials have banned all purses and other bags. Ohio State officials say only that ‘‘security and safety procedures for home football games … will be maintained at their current levels.’’

Ohio State spokeswoman Shelly Poe responded earlier this week to an AP e-mail, saying, ‘‘I can tell you that it is always extremely high security for our home games because of the proximity of Chemical Abstracts, the hospitals and Battelle to the stadium — every game day is a high-level target.’’

Chemical Abstracts is a large private company which adjoins campus and is about a half mile or so north of the football stadium. Chemical Abstracts’ Web site bills the company as ‘‘the largest collection of substance information — as well as indexed references from more than 10,000 major scientific journals and 59 patent authorities around the world.’’