Democrats added five top Senate targets to their list of so-called "BP Republicans," a group Democrats charge with favoring oil companies' business interests.

Democrats accused four Republicans running for Senate, along with one incumbent defending his seat, Sen. David Vitter (R-La.), of "standing up for BP and other oil companies while ignoring the needs of" workers in their states.

The latest batch of GOP candidates mark a continuation in a campaign started first after Rep. Joe Barton (R-Texas), the ranking member of the House Energy and Commerce Committee, apologized to BP's CEO earlier this summer during hearings on the Gulf of Mexico oil spill. 

Republicans dismissed the attack as a distraction.

"Silly political tactics like this remind voters how far Democrats in Washington have fallen in recent months. Instead of being able to run on their own agenda, they're forced to rely on increasingly desperate attacks  because they can't answer the number one question on the minds of voters - where are the jobs?" asked Brian Walsh, the communications director for Senate Republicans' campaign committee.

Democrats pounced on Barton for apologizing to BP for the way the U.S. had treated the oil company, and have sought to carry it throughout the summer, though now the company is on the verge of officially sealing shut the leak that had caused the worst oil spill in history.

The Republicans include: Wisconsin Senate candidate Ron Johnson, Washington Senate candidate Dino Rossi, Pennsylvania Senate candidate Pat Toomey, Indiana Senate candidate Dan Coats, and Vitter. The five join Barton, a pair of House lawmakers, as well as two other Senate candidates: Sharron Angle (Nev.) and Rand Paul (Ky.).

The choice of which Republicans have been designated "BP Republicans" is no accident; the senate candidates targeted by the Democratic National Committee-led project are all locked in hotly-contested races. Of the six Senate candidates included, four are running for Democratic-held seats, while two are defending GOP seats.

The campaign urges those Republican candidates to "stop standing in the way and start working with President Obama and Democrats" and "move our country forward."