BOSTON (CBS) – The coronavirus crisis forced organizers to officially postpone the 2020 Boston Marathon to Sept. 14th, a first for the 124-year-old race. At Friday’s announcement, Mayor Marty Walsh said he doesn’t want anyone lacing up their sneakers to try and complete the 26.2-mile course on Patriots’ Day.

“I want to discourage anyone from trying to run the course on April 20th,” Walsh said. “I know that runners had their training plans set for that date, but the roads will not be closed for crowds, first responders will not have the ability to be working on those routes.”

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Walsh said he’s heard that some people are talking about running the marathon on the 20th, but “we’re asking you not do that.”

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“There won’t be barriers, there won’t be barricades, there won’t be public safety officials out there. We can’t monitor that situation, we can’t monitor the route,” he said. “If a large group of runners decides to do that, you’re taking resources away, potentially very important resources away from something else.”

Walsh said he wants people to be safe and smart, and to look forward to the opportunity to run in a very unique Boston Marathon later this year.

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“You have a chance to run in a historic once-in-a-lifetime race in September and I hope all the runners and people will embrace it,” he said.