Boston Mayor Marty Walsh, Police Commissioner William Evans, city officials and the Boston Athletic Association held a Thursday morning news conference to discuss public safety measures at this year's Boston Marathon.
Boston Police Commissioner William Evans stressed there has been much training and coordination leading up this year's Boston Marathon.
"We don't want to get complacent after what happened five years ago and that's something we continually stress," Evans said.
Evans said he's spoken to the FBI and there is no known credible threat to this year's marathon on April 16, which comes five years after two bombs planted near the finish line killed three spectators and wounded more than 260 others.
Evans said there will be a heavy law enforcement presence and multiple checkpoints for spectators along the perimeter of the marathon course.
"There will be observation teams up on the roofs. There will be SWAT assets, there will be bomb-sniffing dogs, as well as hazmat Boston police officers working closely with the fire department."
Walsh encouraged spectators not to bring bags or backpacks and to take public transportation.
"We're asking everyone to please cooperate to allow this race to go smoothly and allow this experience to go smoothly," Walsh said. "If you're in a checkpoint and there's a long line, please be patient."
There will be an array of street closings and parking bans throughout the weekend as well as Monday, and Walsh encouraged people to check Boston.gov for details.
Security will be tight along the 26.2-mile course, with up to 8,000 public safety personnel along the route, bomb-sniffing dogs, and aircraft equipped with technology to detect a radiological "dirty" bomb.
Three tethered drones will also be monitoring the course.