• BOSTON (AP) -- The bombs that blew up seconds apart at the finish line of one of the world's most storied races left the streets spattered with blood and glass, three dead, including an 8-year-old boy, more than 140 wounded and gaping questions of who chose to attack at the Boston Marathon and why.
• Federal investigators said no one had claimed responsibility for the bombings one of the city's most famous civic holidays, Patriots Day. But the blasts among the throngs of spectators raised fears of a terrorist attack.
• President Barack Obama was careful not to use the words "terror" or "terrorism" as he spoke at the White House Monday after the deadly bombings, but an administration official said the bombings were being treated as an act of terrorism.
• "We will find out who did this. We'll find out why they did this," the president said. "Any responsible individuals, any responsible groups, will feel the full weight of justice."
• The Pakistani Taliban, which has threatened attacks in the United States because of its support for the Pakistani government, on Tuesday denied any role in the marathon bombings.
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• The deadly explosions at the Boston Marathon reverberated on both sides of the Atlantic as cities from Los Angeles to London saw a surge in security.
• The White House, New York's Times Square, and the preparations for former Prime Minister Margaret Thatcher's funeral in London all had enhanced and intensified law enforcement presence after Monday's two blasts in Boston.
• Police in Los Angeles, Washington, D.C., Detroit, San Diego and Las Vegas monitored landmarks, government buildings, transit hubs and sporting events. Law enforcement agencies also urged the public via Twitter and Facebook to report suspicious activity to the police.
• British police were also reviewing security plans for Sunday's London Mara

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