Explosions Rock London; Dozens Are Killed

* On Wednesday, thousands of people in London, England, celebrated the city being chosen as the site for the 2012 Olympic Games. Yesterday, the city was in shock as explosions on at least three trains and on a bus killed more than three dozen people and injured hundreds more.

British police and government officials say that four explosions happened between 8:50 a.m. and 9:50 a.m. London time, when thousands of people were heading to work. (That was between 3:50 a.m. and 4:50 a.m. in Washington.)

Officials say the attacks were done by terrorists but don't know yet if they were carried out by members of al Qaeda, the group responsible for the Sept. 11, 2001, attacks at the Pentagon and in New York City and Pennsylvania.

What happened in London also had an effect on people here. If you were riding the Metro around Washington yesterday, you may have noticed more police officers -- some with dogs -- in stations and on trains. City officials boosted security on trains and buses. Those precautions probably will last for several days.

President Bush was in Scotland to meet with seven other world leaders when the explosions happened. He said that the United States and other countries will work against terrorists.

"We will find them; we will bring them to justice," he said.

Emergency vehicles at London's King's Cross station, near the site of a blast.An Amtrak police officer and his K-9 partner at Washington's Union Station.