Boston Mayor Martin J. Walsh and city officials had a message Friday for Boston Marathon spectators, along with fans of the Boston Bruins and Red Sox.

“It’s going to be a beautiful day,’’ Walsh said at a City Hall news conference. “I hope you can come join us.’’

The conference was held to discuss security at Monday’s race. Officials said there will be a heavy police presence, both uniformed and undercover, along the route.

Dozens of police officers have received behavioral recognition training that helps them recognize certain body language that suggests a person may do something violent, said Boston Police Commissioner William Evans.

To increase security, police will park large trucks and ­machines on side streets along the route to guard against the threat of terrorists using ­vehicles to plow into crowds, as has happened recently in ­London; Nice, France; and Stockholm. Evans stressed that the ­measure, new to the race this year, was a precaution.

“We are really locking down this route,’’ he said.

City officials also outlined parking restrictions for Monday and what people are ­allowed to bring to the race. They asked for spectators’ ­patience as security measures are conducted.

For example, bomb-sniffing dogs and their handlers will be checking sidewalks on Boylston Street, which may require fans to move to the next block if crowds are too heavy.

Monday is expected to be relatively warm, and officials said medical services will be staffed to handle the needs of runners and spectators. ­Hospitals have also beefed up staffing.

Earlier this week, Harvard researchers reported that road closures during marathons in 11 cities could delay ambulances and that elderly people living near the route are more likely to die within a month if they suffer a heart attack or cardiac arrest on the day of the race, compared with other days. The study did not have data specific to Boston.

Evan Allen can be reached at evan.allen@globe.com. Follow her on Twitter @evanmallen.