(Washington) The Secret Service and the FBI have begun separate investigations into cyber attacks on sites opposing proposed constitutional amendments to ban same-sex marriage in California and Florida.

The attacks brought down both sites for several hours.

In a denial-of-service attack, an attacker attempts to prevent legitimate users from accessing information or services. By targeting a computer and its network connection, or the computers and network of the sites, an attacker may be able to prevent someone from accessing e-mail, Web sites, online accounts such as banking, or other services that rely on the affected computer. 

The most common and obvious type of DoS attack occurs when an attacker “floods” a network with information.

The Sacramento-based “No on Prop 8″ campaign said the attack on its server came from California, Texas, New Jersey and Georgia. 

“The attacks to the site increased from a small number of hosts to dozens. As IP addresses of attackers were blacklisted, new IP addresses emerged and attacked,” the group said in a statement.

“I’m sure we’ll hear a lot of denials today from the Prop 8 campaign, but this is clearly an orchestrated attempt to tear down what has become one of the largest grassroots movements in California electoral history,” said Patrick Guerriero, No on Prop 8 Campaign Director. 

“We have reported this to the FBI and other federal authorities and we have secured our site in ways we never thought would be necessary. But make no mistake – this was an attack against individual rights, not just a Web site.”

The Florida “Say No 2″ campaign in a statement said the attack on their server came a crucial time. 

“Their attack was well timed since today is the last day we can take contributions. It’s obvious the supporters of Amendment 2 will stop at nothing to slow us down,” said campaign manager Derek Newton.

There is no direct evidence at this point to link groups supporting the proposed amendments to the attacks.  But those groups also have not condemned the attacks.