This story has been updated.

National Democrats will announce Friday that they are launching online ads against George Allen, the leading candidate for the Republican Senate nomination in Virginia, to point out what they say is his willingness to protect billions in tax breaks for oil companies that contribute to his campaign.

Former Virginia Governor and U.S. Senator George Allen (Bill O’Leary/The Washington Post)

After clicking on the ads, which will run for several weeks, supporters are directed to the DSCC’s Web site, where they can add their names to an online petition.

Allen’s campaign did not immediately respond to a call for comment.

But the National Republican Senatorial Committee weighed in.

“National Democrats are apparently hoping Virginians will overlook that it’s not only their party who currently controls the Senate, but it was their own Democrat leadership who jettisoned it because of opposition from fellow Democrat Senators,'' said Chris Bond, a NRSC spokesman. "So this cheap political stunt from Tim Kaine’s liberal buddies in Washington simply reminds Virginians that Kaine’s support for raising taxes in this economy puts him to the left of even members of his own party.''

Allen is expected to face Kaine, a former governor and the leading candidate for the Democratic nomination, in the general election.

Since the start of his congressional career, Allen has received nearly $445,897 in campaign contributions from the oil and gas industry.

We reported last month that Allen earned nearly $350,000 from his consulting business that lists energy as one of its top priorities, and was paid at least $10,000 in consulting fees from a pair of the nation’s largest coal companies — Alpha Natural Resources and Peabody Energy. A separate nonprofit organization he formed after leaving the Senate tries to influence the public debate about energy in part with contributions from the industry.

This week, Allen published an op-ed urging the Obama administration to approve the construction of an advanced pipeline linking Canada and the United States.

As a senator, Allen voted for tax breaks to oil and coal companies and against fostering alternative sources, including solar and wind, because he said they were not dependable. Democrats say that those are equal to $21 billion in taxpayer subsidies.

“For too long, George Allen has worked to protect multi-billion dollar tax breaks for his big oil contributors. Now oil company profits are soaring and Virginia families are struggling. It’s time for him to stop collecting campaign contributions from the industry and then doing their bidding,” said Matt Canter, a spokesman for the Democratic Senatorial Campaign Committee. “Our campaign will rally opposition to Allen’s policies that put his big campaign contributors ahead of Virginia families.”

The DSCC will announce the ads the same week that several companies are announcing profits for the third quarter of the year.

The DSCC will also target Republican senate candidates in Montana (Denny Rehberg), Arizona (Jeff Flake) and Nevada (Dean Heller).

Allen, who faces a crowded field of opponents in June’s Republican primary including tea party leader Jamie Radtke, is primarily running on economic issues, spending and taxes.

He is expected to face Kaine, a former governor and chairman of the Democratic National Committee, in the November 2012 election to replace retiring Sen. James Webb (D).

Kaine’s campaign did not immediately return an e-mail requesting comment on his stance on the Keystone XLProject linking Canada and the United States.