Boston Marathon explosions

Mass transit security heightened in St. Louis

St. Louis Police Chief Sam Dotson said it is too soon to say if the events in Boston will result in greater security at public events in St. Louis.

Obama: Boston culprits to feel 'weight of justice'

"We will find out who did this. We'll find out why they did this," President Barack Obama said.

AGGREGATION: Where to find live coverage of Boston Marathon explosions

Reports are streaming out of Boston after two bombs exploded near the finish line of the Boston Marathon. We've aggregated a list of sources for live coverage of the explosions.

Columbia runners in Boston Marathon appear to be safe

All the Boston Marathon runners who listed themselves as being from Columbia have been accounted for and appear to be OK.

Security beefed up worldwide after Boston Marathon blasts

Agencies were also stepping up their social media response, telling the public via Twitter and Facebook to report suspicious activity to the police.

Obama calls Mass. officials after explosions

Obama also told Mayor Tom Menino and Gov. Deval Patrick that his administration would provide whatever support was needed in responding to the incident, the White House said.