The Cambridge Fire Department is responding to a report of a manhole fire on JFK Street in Harvard Square, said Dan Riviello, director of communications and media relations for Cambridge Police just before 12:30 p.m. Friday.

All nearby residents and businesses were being evacuated as a precaution, he said, although no injuries had been reported.

Cambridge Police were on the scene diverting traffic, as JFK Street between Eliot and Mount Auburn streets were closed to pedestrian and vehicle traffic, he said. People were asked to avoid the Harvard Square area and seek alternate routes, as some traffic signals weren’t working.

Update: By 1:05 p.m., the threat of an underground fire had been controlled and put out and a power outage had been isolated to one block of buildings in Harvard Square at JFK Street.