New airport security rules mean travelers from 14 countries including Nigeria and Yemen will be subject to mandatory extra screening – including full-body pat-downs – before they can board a flight to the US.
Responding to critics of what is seen as his measured approach, Obama says the “nation is at war against a far-reaching network of violence and hatred." He calls for national unity.
Airport security measures change in response to every plot, and the Christmas Day terrorist attack is no different. But use of screening technologies hasn't kept up with new terrorist methods.
Terrorism on 9/11 permanently altered how passengers respond to airline hijackings, rewriting the conventional wisdom that the best way for passengers to stay safe is to stay quiet.
Nigerian Umar Farouk Abdulmutallab, who attempted to bomb a Northwest flight on Christmas day, claims ties to Al Qaeda in Yemen, pressuring the Obama administration's plans to shut down the Guantanamo prison facility. Nearly half of its detainees are from Yemen.
In both cases, passengers and crew subdued the alleged bomber before the explosive material could fully ignite. In the Detroit attack, passengers heard popping noises and saw suspect Umar Farouk Abdulmutallab's pants on fire when they intervened, according to court documents.
From 9/11 to the Christmas Day attack on Northwest Flight 253 over Detroit, terrorists have changed their tactics to get around airport security.
The UK says the US could learn from its counter-terrorism strategies to handle militant Islamists, which include increased cooperation between intelligence agencies and reaching out to Britain's 2.5 million Muslims.
Khalid Sheikh Mohammed and four others are to stand trial in New York. Here's the evidence federal prosecutors will use against them.
At least 21 plots to launch attacks on American soil have been thwarted. Here's a chronology.