More than 4,000 groups and websites have signed on to support a day of protest against U.S. National Security Agency surveillance programs, scheduled for Tuesday.

In addition, tens of thousands of people have pledged to make calls and post messages on the Web in support of surveillance reform, said organizers of The Day We Fight Back.

Among the groups supporting the day of Web protest are the American Civil Liberties Union, Amnesty International, BoingBoing, Demand Progress, the Electronic Frontier Foundation, Fight for the Future, Free Press, Mozilla, Reddit and Tumblr.

"Together we will push back against powers that seek to observe, collect, and analyze our every digital action,” organizers wrote on TheDayWeFightBack.org. “Together, we will make it clear that such behavior is not compatible with democratic governance. Together, if we persist, we will win this fight.”

Supporters of the NSA surveillance program say they help keep the U.S. safe from terrorist attacks.

Organizers of the protest are encouraging websites to display banners calling for a scaling back of NSA surveillance program. The groups will encourage people to call or email members of the U.S. Congress and to post Twitter messages, write Facebook posts and engage in other online activity.

Many organizers hope the protest will spur Congress to pass the USA Freedom Act, a bill that would scale back the NSA’s bulk collection of U.S. telephone records. The bill, introduced in October following leaks about NSA surveillance from former contractor Edward Snowden, has more than 140 co-sponsors between its versions in the Senate and House of Representatives.

Organizers are modeling the protest after one two years ago that helped defeat two online copyright bills, the Stop Online Piracy Act and the Protect IP Act. Ironically, Senator Patrick Leahy, a Vermont Democrat, was the lead sponsor of the Protect IP Act and is now the lead sponsor of the USA Freedom Act, the NSA reform bill supported by the protest groups.

"We will not stand idly by while the freedom of the Internet is threatened by abusive government surveillance,” David Segal, executive director of Demand Progress, said in a statement. “We will unite as a community, and we will defend this vital resource. And we are strong.”