30,000 runners and 500,000 spectators may be under a more watchful eye by local and federal law enforcement at this year’s Boston Marathon.

According to a report from ABC News, law enforcement officials will be monitoring various potential targets during this year’s race, especially in those areas with the largest number of people.

Law enforcement agencies cited a number of social media posts calling for violence, as well as the marathon coinciding with several religious holidays and the dates of previous attacks as cause for their concern, according to the report.

“The safety of everyone involved in the Boston Marathon is always our priority” Lauren Proshan, Chief of race operations and production at the Boston Athletics Association (BAA) said in an email. “We continue to plan for a safe and secure marathon weekend, though the BAA does not speak to specifics of the security plan”

“We want to again thank the police and law enforcement personnel who work year round with us and in our planning.”

Proshan added that all spectator guidelines can be found on the BAA website or on the BAA Racing App.

William Evans, executive director of public safety and chief of police at Boston College and former Boston Police commissioner, said that any event that gathers a great number of people runs some risk of becoming a target and pointed to the New Year’s Eve attack in New Orleans as an example.

“Bag checks, getting the public to, if they see something out of the ordinary, to let us know. But, as you know, there’s been unfortunate terrorist attacks around the world. I think we’ve seen it in New Orleans on New Year’s Eve,” he said. “I think with so much unrest in the world right now, most police agencies around the country have, if you’re going to do special events, really have to make sure they can do their best to secure it.”

The key, Evans said, is that law enforcement and everyone involved want a safe and secure race route this year. They don’t want people to jump the barriers or cross the route. He urged spectators to cooperate with race officials and the police to ensure the marathon is as safe as possible.

Specifically, he added, officials appreciate it when the public keeps things like bags and coolers at home.

“There’s a lot of unrest in the world unfortunately, and people feel unsettled,” said Evans. “I think with that, law enforcement has to up their game in securing any event and also asking the public’s help for it.”

In an April 4 letter to area college and university students, Boston Police Commissioner Michael Cox wrote that the department has planned security measures for marathon events throughout the weekend. Cox added that spectators should expect a significant presence of uniformed and plain clothes officers from many agencies along the 26.2-mile course.

Cox also provided several tips for spectators ahead of the race, urging the public to refrain from public drinking and carrying open containers, be careful of drinks, as they’ve seen incidents of drink spiking and to be aware of cellphone thefts, among others.

Both Cox in his letter and Evans recommended that people take public transportation and take notice of race related road closures throughout the day.

“Again, a marathon is very difficult to secure,” Evans said. “It’s 26.2 miles. We need the public’s help to help us secure and make it a great event, which it always is.