Hacker group "Anonymous" has allegedly threatened to attack the New York Stock Exchange's website on Monday in support of demonstrators who've been arrested during the Occupy Wall Street protests.

Online messages, purportedly posted by members of the loosely organized coalition threaten to "erase" the NYSE from the Internet as retaliation for the arrests, ABC reported Monday.

The first threat was made five days ago as demonstrators fanned out into the streets of lower Manhattan, launching a protest movement against corporate greed and economic inequality.

A YouTube video reiterating the threat surfaced online on Saturday, after the NYSE appeared to shrug off the initial warning.

"Many people refuse to accept that Operation Invade Wall Street is a reality," a computer-generated voice says in the video. "I am here to clarify that factions of Anonymous are going with the operation. Other factions are opposing it."

Given the nature of the loose-knit hacktivist collective, the legitimacy of the threats is unclear.

A YouTube video allegedly posted by the group last Friday counters threats to attack NYSE.com on Monday, saying Anonymous wouldn't attack NYSE on Columbus Day "as it is completely irrelevant."

In August, the hackers and forum-dwellers who comprise the "Anonymous" collective have pledged to take social networking site Facebook down on Nov. 5 over privacy concerns.

Last July, investigators in the U.S., Britain and the Netherlands arrested 21 people who were allegedly involved with the group's attack on PayPal Inc., an online payment company that had refused to process donations to WikiLeaks.

Threats from the hacker collective are often driven by the desire for political or social change, motivations shared by the Occupy Wall Street protesters.

The Occupy Wall Street demonstrations started in New York last month as a protest allowing participants to voice their anger against corporate greed, the government and the economy.

The demonstrations have since gained stream, spreading across North America with several similar protests planned in other parts of the United States and Canada.

While detractors have criticized the movement for its loose organization, U.S. House Leader Nancy Pelosi has backed the protest's overall message.

"I support the message to the establishment whether it's Wall Street and the political establishment and the rest. The change has to happen," she said in an appearance on ABC News' This Week.

With files from The Associated Press