Explosions in London. At least 300 injured, 45 dead.

This BBC article has the latest info on this unfolding tragedy. I'm not going to pursue the story until more concrete information comes out, although I'll update this post over the course of the day.

New York is on a heightened alert this morning, and extra precautions are being taken in DC. There are currently no other alerts from the State Department.

UPDATE: As of 11:55 am, the national terror alert level is being raised to orange respecting mass transit systems.