Tragic

Thoughts and prayers:

At least 33 people were killed when three explosions ripped through London subway trains Thursday and an undetermined number were killed in a fourth explosion on a bus, officials said in what Prime Minister Tony Blair described as a "barbaric" terrorist attack.

U.S. law enforcement officials earlier said the death toll from the four blasts was at least 40.

Some 45 people were in serious or critical condition, London officials told reporters Thursday afternoon in describing the worst attack on London since World War II.