A collective of hacker groups plans to attack the websites of major government agencies and banks on Tuesday to protest American foreign policy.

For weeks, the groups, which include Anonymous, have used social media to publicize their planned operation, dubbed "#OpUSA." In a post on the file-sharing site Pastebin, one member of Anonymous laid out an ambitious list of targets, including the websites of the White House, the Defense Department, the FBI, Bank of America and Chase Bank.

“Anonymous will make sure that this May 7th will be a day to remember,” another post from Anonymous said, adding the planned attacks are meant as a response to "multiple war crimes" committed by the United States in Iraq, Afghanistan and Pakistan.

In the past, however, Anonymous has hyped plans to launch coordinated attacks but ended up having little impact, security experts say. Last month, Anonymous launched #OpIsrael, which promised to “wipe Israel off the internet.” That operation was "a total failure," Ronen Kenig, director of security solutions for Radware, told The Daily Beast last month.

Tuesday's planned operation still has the U.S. government's attention. The Department of Homeland Security issued an alert last week warning about the event that "likely will result in limited disruptions and mostly consist of nuisance-level attacks against publicly accessible webpages."

Hackers based in the Middle East and North Africa plan to participate in the attacks targeting U.S. government, financial, and commercial institutions, according to the DHS alert, which was first reported by the security blog Krebs on Security.

"Independent of the success of the attacks, the criminal hackers likely will leverage press coverage and social media to propagate an anti-US message," the alert said.

Tuesday's operation comes as hackers based in the Middle East have generated increased attention. Since last fall, a group that calls itself the Izz ad-Din al-Qassam Cyber Fighters has claimed responsibility for disrupting the websites of several major U.S. financial institutions, including JPMorgan Chase, Wells Fargo and Bank of America. U.S. officials claim the group is linked to the Iranian government, but have not offered proof of such a connection.

In recent weeks, another hacking group that calls itself the Syrian Electronic Army has taken credit for hacking the Twitter accounts of several news agencies, including NPR, Reuters, BBC and Al Jazeera. Security experts say the group appears to have ties to the Syrian government.

The group's attack last month on the Twitter account of the Associated Press sent out a fake tweet about an explosion at the White House that injured President Obama. The tweet, which was re-tweeted thousands of times within minutes, caused the Dow Jones Industrial Average to drop sharply before the stock market index quickly recovered.

UPDATE: By 4 p.m. Tuesday, the operation appeared to have largely fizzled.

The website Hackers News Bulletin claimed to keep a list of more than 600 sites that were defaced in the operation, dubbed #OpUSA. But most of the sites listed -- if they had been brought down -- were largely unknown to the general public. One site, yourchessgames.com, appeared to have been replaced Tuesday with a message from Anonymous.

Marty Meyer, president of Corero Network Security, told The Huffington Post that his company had several customers on the hackers' list of purported targets, but "we haven't really seen anything yet."

He said #OpUSA appeared to have "no real focus" and doubted the hackers had access to the large botnets, or networks of infected computers, needed to launch large-scale attacks that can bring down major websites.

"It's kind of a non-event," Meyer told The Huffington Post.