The bombing of a packed London commuter train on Friday prompted officials to beef up security on New York City's subway system, major commuter rail networks, at airports and other locations.

The Metropolitan Transportation Authority, which operates mass-transit lines in New York City and the Long Island Rail Road and Metro-North commuter lines, said it was closely monitoring the investigation of the fiery blast that injured 29 people in a West London underground station.

The MTA will expand bag screening and deploy extra police patrols on the LIRR and Metro-North, as well as in midtown Manhattan's Grand Central Terminal and Pennsylvania Station, "out of an abundance of caution," spokesman Kevin Ortiz said.

MTA officials were also consulting with New York City police about bolstering security in the subway system, he said.

New York state Governor Andrew Cuomo said in a statement he had also directed authorities to increase security at airports, bridges, tunnels and other sensitive locations across the state.

"On behalf of all New Yorkers, I condemn the apparent terrorist attack in London today in the strongest possible terms," Cuomo added.

The NYPD said it has been in contact with London law enforcement officials and has added officers, some heavily armed, and bomb-sniffing dogs to the city's transit system.

Across the country, Los Angeles police said in a statement they had beefed up their presence on subway, commuter train and bus lines in response to the attack in London.

Amtrak, the country's nationwide passenger rail carrier, said it was closely following the events in London but was not adding to the layers of security it already has in place.

"Robust security measures are in place at stations, on trains and along the tracks, and partnerships with federal agencies to gather intelligence information are underway," Amtrak said in a statement.