In a press statement, LulzSec said that in a new operation - Codenamed Operation Anti-Security - both organisations will "encourage any vessel, large or small, to open fire on any government or agency that crosses their path."
"We fully endorse the flaunting of the word `AntiSec' on any government website defacement or physical graffiti art", added the press statement.
According to the statement, the "Lulz Lizard battle fleet is now declaring immediate and unremitting war on the freedom-snatching moderators of 2011" - a thinly-veiled reference to various governments attempting to regulate the Internet.
"Top priority is to steal and leak any classified government information, including email spools and documentation. Prime targets are banks and other high-ranking establishments", the hacktivist group adds.
"It's now or never. Come aboard, we're expecting you..."
Infosecurity's sources suggest that the pooling of resources between Anonymous and LulzSec is being taken seriously by law enforcement agencies on both sides of the Atlantic, and that arrests are likely in the days ahead, building on the arrests carried out in Spain and Turkey earlier this month.