The FTC tells donors to do their research about organizations seeking money, and to be on guard about organizations they do not know or trust. It also advises never to send cash, which cannot be traced, and never to give out personal information to charities that don't seem reputable.
The agency runs a "Charity Checklist" that consumers can consult before deciding to donate money.
State officials have also warned about potential scams. On Wednesday, Massachusetts Attorney General Martha Coakley issued a statement advising "people to do their homework on the charity before giving to ensure their money will go to the purpose they intend.”
Three people were killed and more than 170 were injured in Monday’s attack. Early Friday, one suspect in the bombing and a Massachusetts Institute of Technology police officer were killed, as police tried to close in on the suspects, who are brothers. The search for the remaining suspect has shut down most of the city and its surrounding suburbs.
According to the state's Undersecretary for Consumer Affairs Barbara Anthony, within four hours of the attack more than 125 online domain names were registered claiming to collect money for victims.
“It is unspeakable that anyone would sink to capitalize on Boston’s sorrow as we recover from this tragedy," she said in a statement. “We remind consumers to exercise caution and do their homework before reaching out to help.”
Officials in other states have issued similar statements.