State Sen. Mark Herring, a Democrat who represents Loudoun and Fairfax counties, announced Tuesday that he will run for attorney general in 2013.

Herring kicked off his campaign by taking a shot at the current attorney general, Ken Cuccinelli II (R), whom he accused of using the office for an “ideological crusade,” and at the Republicans running to replace him.

“It’s time to get politics out of the attorney general’s office and return its focus to doing what’s right for the people of Virginia,” Herring said. “Virginia cannot afford another attorney general like Ken Cuccinelli.”

Cuccinelli has garnered national attention for suing the federal government over the health-care overhaul, advising colleges that they could not adopt policies protecting gay people and subpoenaing climate-change documents from the University of Virginia.

Herring filed his candidacy paperwork with the State Board of Elections on Tuesday, joining a growing number of candidates who have announced they will seek statewide office next year.

Many have been lining up since Cuccinelli announced in December that he would not run for reelection but instead would challenge Lt. Gov. Bill Bolling (R) in the race for governor.

On the Democratic side, Mike Signer, an unsuccessful candidate for lieutenant governor in 2009, is expected to run for attorney general, according to several Democrats familiar with his plans but not authorized to speak publicly.

Former House minority leader Ward L. Armstrong (D), who lost his seat after Republicans eliminated his largely rural district in the southern part of the state, also is considering running for attorney general.

As for Republicans, Del. Robert Bell (Charlottesville) has said he is running and Sen. Mark Obenshain (Harrisonburg) said he is exploring the possibility.

Herring was elected to the Senate in 2006. He has worked to expand technology-based economic development, make state and local governments more accountable, ban new synthetic drugs and protect seniors from financial scams.

“As I have done in the Senate, I will work to keep Virginia’s families and seniors safe,” he said. “I will fight to protect consumers, defend civil rights and ensure state agencies are accountable to the people. And I will stand up for the right of women to make their own health-care decisions without government interference.”

Herring, who has lived most of his life in Loudoun County, practices law in Leesburg. He previously served as a Loudoun County supervisor for four years.