Republicans are preparing for a "blitzkrieg" of attacks against Democrats, Vice President Joe Biden warned in a letter to supporters.

The forceful language came in a fundraising e-mail for the Democratic Congressional Campaign Committee, in which Biden warned that the GOP would use any means necessary to take back the House.

"As things heat up, you can expect House Democrats will be hit with a GOP blitzkrieg of vicious Swift-Boat-style attack ads, Karl Rove-inspired knockout tactics, thinly veiled attempts at character assassination and tea party disruptions," Biden wrote.

Keeping the House, the veep wrote, is all about money.

"Our strategists are looking at the midterms from every angle, and we know what must be done to sustain our Democratic Majority — it's simply a matter of having the financial resources required right now to most effectively help targeted incumbents," he said.