NEW YORK (CNN/Money) - Democratic senators are seeking a federal probe of Sinclair Broadcast Group's plans to air an anti-Kerry film next week, just two weeks before the election.

A still from the movie shows a young Kerry testifying before Congress

Sinclair's vice president told CNN the program is a "newsworthy event" designed to air the stories of Vietnam veterans who believe they were maligned by Kerry after he returned from the war.

Sinclair has ordered its 62 stations to air "Stolen Honor: Wounds That Never Heal" without commercials in prime time next week, just two weeks before the Nov. 2 election. Twelve of those stations are in key battleground states of Ohio, Florida, Iowa and Wisconsin. (Click here for CNN's election coverage.)

A total of 20 Democratic senators led by California Sen. Dianne Feinstein wrote a letter to the Federal Communications Commission (FCC), calling for an investigation into whether Sinclair's plan to air the film is an improper use of public airwaves, said Adam Vogt, a spokesman from the senator's office.

The FCC told CNN it has the letter, but would not comment further. See the letter here, and the names of 17 of the 20 senators who signed it.

Michael Copps, one of the four FCC commissioners, said Sinclair's action is "an abuse of the public trust."

"It is proof positive of media consolidation run amok when one owner can use the public airwaves to blanket the country with its political ideology -- whether liberal or conservative," Copps said in a statement obtained by CNN/Money.

Meanwhile, the Democratic National Committee plans to file a complaint with the Federal Election Commission alleging that the documentary is an illegal contribution of airtime to President Bush's campaign, a committee spokeswoman told CNN/Money.

DNC chairman Terry McAuliffe told CNN the complaint charges that Sinclair's plan is an "illegal in-kind contribution to the Bush-Cheney campaign."

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"This is a group that is going to preempt their airtime to run a 90-minute documentary attacking Senator Kerry," McAuliffe said on CNN's American Morning. "This is a use of corporate funds. Under the law, you cannot use corporate funds to go out there and advocate for a party or a political candidate."

The FEC has civil authority to enforce the Federal Election Campaign act, which prohibits a corporation or union from making a contribution or expenditure to a candidate in a federal election.

But it doesn't apply to broadcasters producing a news story or editorial unless the facility is owned or controlled by a political party or candidate, said FEC spokesman George Smaragdis.

A party found violating the act will be charged a fine to be paid to the U.S. Treasury.

In a press release, the DNC attacks Sinclair for being a conservative media outlet with ties to the Bush administration, pointing to campaign finance contributions made by Sinclair executives as evidence of their political leanings.

For the 2004 election, Sinclair executives have donated nearly $59,000 to the Bush-Cheney campaign or the Republican National Committee (RNC), including a $50,000 gift to the RNC from Sinclair Vice President Fred Smith, reported CNN.

A Bush campaign spokesman said the camp has nothing to do with Sinclair Broadcasting, the anti-Kerry film or Sinclair's plan to air the film just before this year's tight election.

Mark Hyman, vice president for corporate relations at Sinclair, told CNN that broadcasting the film is not a violation of campaign finance law.

"Our goal here is to get John Kerry to sit down and talk with these guys. Get a chance to tell them why he branded them as war criminals, why he accused them of committing war-time atrocities," Hyman said.

"Is it (illegal) because there are some elements of this that may reflect poorly on John Kerry?" Hyman asked.

"If you use that logic and reasoning, that means every car bomb in Iraq would be an in-kind contribution to John Kerry. Weak job-performance ratings that came out last month would have been an in-kind contribution to John Kerry."

Sinclair said on its Web site that Sen. Kerry has been invited to participate in the broadcast.

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Hyman said Kerry's campaign has not yet responded. But he said he was hopeful "they may change their minds and join us, because we think it's an important debate issue that needs to be addressed."

McAuliffe said the DNC would only be interested in having Kerry respond, if Sinclair would give the Democratic candidate 90 minutes in prime time as well.

Ken Mehlman, manager of President Bush's re-election campaign, told CNN the Bush-Cheney campaign has suffered its share of media attacks and didn't file any complaints.

"We had ("Fahrenheit 9/11" documentary creator) Michael Moore, we had CBS, which they had false documents. Having experienced over the course of a number of years what I consider to be a media bias in some cases I'm not in the business of dealing with filing complaints against media organizations," he told CNN, adding that he was not familiar with the documentary Sinclair will broadcast.

McAuliffe said the program would be a different story, if the documentary was offered on a pay-per-view station so people could choose whether or not to watch it.

Sinclair (down $0.09 to $7.29, Research) stock fell more than 1 percent in midday Nasdaq trading.  

-- CNN contributed to this report