Authorities echoed the call for vigilance.
“We do not want people to live in fear,” Procopio said. “All we ask is that they continue to be alert to anyone or anything that doesn’t look right and call 911 immediately if they do see something.”
Currently, spectators must pass through one of three entrances to the lawn in front of the Hatch Shell to have their bags checked. Alcoholic beverages, glass containers, large tarps, and any sharp objects are confiscated. After 6 p.m., admission is closed due to “crowds and public safety concerns,” according to the event website.
While bags are fully searched, there are no metal detectors.
Edward F. Davis, the Boston police commissioner, said Friday that after the Marathon bombings, authorities are renewing efforts to provide “the highest level of security possible.”
“We’re going to be there July Fourth to make people feel safe,” he said. “They should not be afraid to come into the city.”
As graduation season begins, colleges have also taken steps to bolster security, as Northeastern did Friday.
“I think in the current environment, it’s in everyone’s best interest to be careful,” said Ellen de Graffenreid, a spokeswoman for Brandeis University, which will have a heightened police presence at its May 19 ceremony.
Simmons College is asking attendees not to bring large bags and not to leave any belongings unattended.
“Public venues throughout the country are increasing security in light of these events; this should not be viewed as an indication of any increased threat to the Boston area,” the college said in its announcement.
Roger Cressey, security consultant and former White House counterterrorism adviser, said universities are doing their best to make guests feel safe, even if the actual threat is minimal.
“The message [colleges] must have is that we acknowledge this is a higher time of security awareness, and we are taking action,” Cressey said.
Brian Ballou of the Globe staff and correspondent Katherine Landergan contributed to this report. Meghan Irons can be reached at firstname.lastname@example.org.