American Airlines halts flights due to network outage

The grounding of American's entire flight schedule follows the closing of a terminal at New York's LaGuardia Airport on Tuesday morning because of a suspicious package.

The disruptions have come amid heightened security concerns following the bombing of the Boston Marathon finish line on Monday.

Following the bombing, the Federal Aviation Administration (FAA) grounded all flights at Boston's Logan International Airport and restricted the air space over the sight of the incident.

Boston's "T" subway system similarly briefly suspended service on its Green line at stations near the bombing area.