Belgium's capital woke Saturday to a security lockdown as the national crisis center raised its terrorism alert to its highest level and at least one suspect from the Paris attacks remains at large. Authorities across Europe, the Mideast and in Washington are trying to determine how a network of primarily French and Belgian attackers with links to Islamic extremists in Syria plotted and carried out the deadliest violence in France in decades — and how many may still be on the run. Belgium's national Crisis Center raised its terrorism alert for the Brussels region to Level 4, which indicates a "serious and immediate threat." The Belgian capital was home to the suspected organizer of the Nov. 13 Paris attacks, Abdelhamid Abaaoud, and Belgium has filed charges of "participation in terrorist attacks and participation in the activities of a terrorist organization" against three suspects relating to the Paris attacks. Heavily armed police and soldiers patrolled Saturday morning at key intersections of the Belgian capital, a city of more than 1 million that is home to the headquarters of the European Union, the NATO alliance and offices of many multinational corporations. Residents were recommended to avoid gatherings, train stations, airports and commercial districts. Service was halted on the Brussels Metro, as well as on streetcar lines that run underground, and residents were urged to stay indoors.
