This post has been updated.
Logan International Airport in Boston is experiencing some delays in service, according to FlightStats.com, after two explosions at the Boston Marathon on Monday left at least two dead and more than 20 injured. A separate explosion at the JFK Library appears to be fire-related and unconnected to the other blasts, according to officials.
Earlier, the airport tweeted that the FAA had issued a "ground stop," around 1:50 p.m. Pacific time, which would hold planes at their point of departure and prohibit them from landing in Boston. The FAA also tweeted to pilots: "Short notice" There is a TFR [temporary flight restriction] in Boston, MA." Passengers heading in or out of Logan Airport should check with their airline about the status of their flight times.
In addition, the Associated Press reports that security has been beefed up in Los Angeles, New York and other cities, even London, which has a marathon planned for Sunday.
The JoeSentMe website for business travelers also reports beefed up security in major cities. It says to expect more security on public transportation and at major buildings, especially the big downtown hotels, in Boston.