Baltimore-area authorities announced heightened security after bombings at the Boston Marathon on Monday, though officials emphasized there was no evidence of threats here.
At least three people were killed and scores were injured in the blasts, which occurred at the finish line of the marathon.
Public safety officials described checks on "critical infrastructure" as a precaution. Baltimore police said fans at Tuesday's game between the Orioles and Tampa Bay Rays at Camden Yards might see tactical officers deployed outside the stadium as they step up cautionary patrols. The Maryland Stadium Authority also said there would be enhanced security.
"We do not discuss ballpark security measures in detail, but Major League Baseball already has stringent policies in place, and we are working with MLB and local authorities to further increase security in the wake of this incident," said Greg Bader, the Orioles' vice president of communications.
The blasts put police on alert in major cities across the United States, including in Washington and New York City, sites of the Sept. 11, 2001, terrorist attacks.
Police Commissioner Anthony W. Batts was in the city's Watch Center and conferring with senior command staff about the affected areas, including public transit and places of worship, department spokesman Anthony Guglielmi said.
"There's no credible threats to Baltimore; we've received no intelligence," Guglielmi said. "This is just proactive planning, given what's happening" in Boston.
Vice President Joe Biden was scheduled to be in Baltimore on Tuesday evening for an event previewing the new University of Baltimore School of Law building, which Baltimore police said affected the decision to beef up security.
Baltimore County Police Chief Jim Johnson also directed commanders to begin checking infrastructure sites, according to department spokeswoman Elise Armacost.
The Maryland Transit Administration, which oversees public transit, encouraged riders to call 410-454-7721 to report suspicious activity or unattended packages.
Baltimore Sun reporter Eduardo A. Encina and Reuters contributed to this article.