Countries around the world tightened security on Thursday after a series of deadly coordinated blasts struck the London transport system during the morning rush hour, raising alarm internationally about the possibility of more terrorist attacks. Coming a year after commuter trains in Madrid were bombed and four years after the Sept. 11 attacks in the United States, the events shattered nerves in Europe, where the authorities in France, Spain, Germany, Italy and many other countries held emergency planning sessions, raised terror alert levels and sent additional security personnel into public transport systems.Full Story