Earlier this month the FBI arrested 14 people accused of involvement in last year's cyber-attack on PayPal's Web site by Anonymous in retaliation for the company's closure of a donation account for Wikileaks.

Anonymous has teamed with LulzSec under the #AntiSec banner to issue a joint statement, declaring themselves "outraged at the FBI's willingness to arrest and threaten those who are involved in ethical, modern cyber operations".

In a change of tack, the partners are now calling for a legal form of protest, saying "we encourage anyone using PayPal to immediately close their accounts and consider an alternative" and asking people to tweet pictures of their actions.

The call to arms appears to have gathered some momentum, with the #OpPayPal hashtag the number three trending topic worldwide by 12.00 GMT, prompting @AnonymousIRC to tweet: "We hoped for a little impact, but honestly did not expect this. Waiting for NASDAQ to open. Our tip: SELL EBAY! WikiWiki! #AntiSec #OpPayPal"

In a tweet posted late afternoon, Wikileaks says it intends to file suit against eBay and Paypal in the US and Europe in line with its ongoing legal and anti-trust actions against Visa and MasterCard.

Separately, Anonymous' Austrian branch has accessed the bank data of 96,000 people in an attack on the GIS television licence agency's Web site, according to AFP.

Update

By around 13.00 GMT, Anonymous was claiming several thousand accounts have been closed, tweeting: "Just talked to someone close to Paypal. Couldn't give reliable numbers but we seem to have easily cracked the 20k. CANCEL FTW! #OpPayPal"

In another development, the Metropolitan Police Service's (MPS) Police Central e-Crime Unit (PCeU) have arrested a 17-year old male in the Shetland Isles who goes by the handle 'Topiary' and is believed to be the spokesperson for Anonymous and LulzSec. He is currently being transported to a police station in central London.