(CNN) -- With the momentum of Joe Miller's surprising win over Sen. Lisa Murkowski in the Alaska Republican Senate primary, the Tea Party movement is setting its sights on Delaware.
The Tea Party Express on Tuesday announced its support for Delaware Senate candidate Christine O'Donnell, outlining plans for an aggressive campaign effort in the days leading up to the Sept. 14 Republican primary.
The race pits O'Donnell against moderate U.S. Rep. Mike Castle, a two-term Delaware governor and a Congressman since 1993.
The group outlined plans to hold several events for the candidate over the next week, including a rally on the Delaware Capitol Mall Wednesday, and a radio-thon on WDEL that promises to have "big names" calling in to endorse O'Donnell.
The latest effort comes after the group released a series of TV and radio ads last week that support O'Donnell and rail against Castle as a liberal candidate who "just keeps supporting the failed policies of Nancy Pelosi and Harry Reid."
Both candidates' campaigns have become increasingly caustic, especially as Tea Party-backed candidates across the country have picked up win after win against GOP establishment candidates.
The Castle campaign has launched therealchristine.com, a site devoted to aggregating negative news about O'Donnell.
Tea Party Express leaders also reaffirmed their commitment to spending at least six figures in the state.
"We are launching an aggressive multimedia and multi-platform campaign to help propel Christine O'Donnell to victory, and we've only just begun," Amy Kremer, chairman of the Tea Party Express, said in a statement last week.
The group originally planned to spend about $250,000 on the race, but is now considering expanding their presence with TV and radio ad purchases in Philadelphia, Tea Party Express political director Joe Wierzbicki has said.
A similar last-minute media blitz by the Tea Party Express is credited with propelling Miller -- a formerly little known candidate -- to victory over Murkowski, the Republican Party-backed incumbent in Alaska.
And while Miller's upset has Delaware Republicans taking heed, the state's Democratic party is reveling the intra-party fight, taking a similarly aggressive tone against Castle, who recent polls in the state have shown is the currently the frontrunner in the primary fight.
The Democratic Senatorial Campaign Committee released its own web site Tuesday, DSCC.org/waffles, that seeks to portray the moderate Castle as being a hypocrite and having the "habit of flip-flopping around the Washington Beltway." The winner of Delaware's Republican Senate primary will face Democrat Chris Coons in the race for Vice President Joe Biden's former seat.
CNN's Alison Harding contributed to this report.