American cities were put on a kind of alert let's go to ABC's Alex Perez in Chicago Alex. Well that and I can tell you that we have seen a stepped up police. Presents -- more -- police presence at the... See More
American cities were put on a kind of alert let's go to ABC's Alex Perez in Chicago Alex. Well that and I can tell you that we have seen a stepped up police. Presents -- more -- police presence at the city's landmarks like the Chicago theater even here at Union Station many commuters heading home for the evening rush ran into. Bomb sniffing police dogs and extra police officers on hand that city's train stations. And a bus station is now city officials say there has been no specific threat to the city of Chicago but they are not taking any chances of course remaining extra. Vigilant -- Chicago has two major airports O'Hare and midway millions of people pass through airports every year to get from one part of the country. -- the other parts and the authorities at the airports tonight tell us that they are keeping their eyes open for anything suspicious. There -- a Chicago Blackhawks game tonight vs the Dallas Stars that the united -- 20000 people fit. And that stadium and of course we can expect security to be on high alert there. Tonight officials at the game tell us there will be a moment of silence for the victims in Boston. At that Blackhawks game tonight show a heightened sense of security here in Chicago. But many trying to operate as normally as possible given the circumstances Diane. All right thank you so much Alex -- from Chicago we go to Los Angeles also games taking place there of course heightened security measures. And ABC Cecilia Vega is awaiting us there Cecelia. And that's right just like Alex in Chicago we want to emphasize here in Southern California that there has been no credible threat but as you said heightened security. At this evening's Dodgers game the game has yet to begin but there's an increased police presence here. This example of the type of venue that law enforcement from San Francisco to San Diego this evening are focused on. It but areas where large crowds are expected together not just this sporting events but from shopping malls to public buildings government building. And transit -- especially. As Alex mentioned in Chicago we're seeing the same thing here in the Southern California region especially. In airports like Los Angeles international airport. Travelers can expect to see -- Smith sniffing dogs increased police presence extra security as they make their way through the airport not just -- LAX but at airports. All around the region please also in this area reaching out on social media as social media things like -- FaceBook asking the public this evening. To be especially vigilant again we want to emphasize there has been no credible that threat here in Southern California but the message from law enforcement. All around California tonight to the public is to watch out to be alert and to Diane to report any thing that seems out of the ordinary. All right see something say something taking on a whole new heightened meaning thank you so much this area.
This transcript has been automatically generated and may not be 100% accurate.