All Boston mass transit was suspended Friday, and the Watertown area was in lockdown until further notice as police hunted for the marathon bombing suspect.

The entire city of Boston was put on lockdown Friday morning by the Massachusetts governor as police searched for the second of two men believed to have been involved in the marathon bombings earlier this week.

Gov. Deval Patrick said people should shelter in place as authorities engaged in a “massive manhunt” – an extraordinary order that affected nearly one million people.

The second suspect was shot and killed.

Police searched the Watertown neighborhood door to door on foot and in patrol cars early Friday morning. Residents were asked to call 911 if anyone other than police came to doors in the neighborhood.

All services on the Massachusetts Bay Transportation Authority were suspended authorities announced earlier on Friday.

All Boston Public School activities were canceled. All city employees were told to stay in place and not come to work. If they are already at work, they have been asked to stay in place.

Trial courthouses and offices in Cambridge, Brighton, Newton, and Waltham were closed until further notice. Jurors for courthouses at the Suffolk Superior Court and Brooke Courthouses were told to stay home.

People waiting for buses or other transit services should head home and stay there, police said earlier on Friday. No vehicular traffic was being allowed in or out of Watertown, where police engaged in a shootout overnight with men armed with explosives. A no-fly zone was instituted over the Watertown area, the Federal Aviation Administration announced.

Designated portions of the MBTA system might open up again later on Friday, Massachusetts Emergency Management Agency undersecretary Kurt Schwartz said.

All Amtrak service coming into and departing from Boston's South Station was delayed as a result of police activity and Amtrak service was suspended between Boston and Providence, R.I. before all area service was suspended indefinitely around 11 a.m.

Logan Airport officials told NBC News early Friday morning that the airport was open and operating under heightened security.

Megabus suspended at least ten buses traveling between Boston and New York and at least three traveling between Boston and New Haven, Conn. All Peter Pan and Lucky Star bus line services too and from South Station were suspended.

Police said at a press conference that all of Norfolk Street in Cambridge had been shut down early on Friday, and media were warned to leave the area.

Businesses were asked to remain closed. Harvard University announced in a statement on its website that it was closed. Classes were canceled at the Massachusetts Institute of Technology, where a campus police officer was shot and killed. Students at Boston College were told to "remain indoors" and classes were canceled.

Emerson College tweeted that the school was closed until further notice: “Stay at home and where you are.” Boston University said its police were on patrol on campus. A BU graduate student was among the three killed by the bombing on Monday.

"Search for armed suspect continues in Watertown," the Boston Police Department tweeted. "Residents reminded to remain indoors. All vehicle traffic suspended."

Related:

Profile of suspects in Boston Marathon bombing

Nearly 1 million told to stay indoors, transit canceled

Massive manhunt for 2nd suspect after 1st one killed

Photos from Bostonians locked down amid terror hunt

In a video posted to YouTube you can hear the firefight between two suspects and authorities in Watertown, Mass.

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