The influential U.S. Chamber of Commerce plans to do everything in its power to block President Barack Obama's unannounced measure to make government contractors disclose their political spending.

In an interview with the New York Times, Chamber lobbyist R. Bruce Josten warned the measure could result in harassment and protests directed at businesses that worked with the government.

"We will fight it through all available means," he said. "To quote what they say every day on Libya, all options are on the table."

Last week it was revealed that Obama was considering issuing an executive order that would require companies seeking government contracts to disclose contributions to groups that air political ads.

Although the executive order has yet to be issued, Chamber spokeswoman Blair Latoff blasted the measure as a "political litmus test for companies that wish to do business with the federal government."

When asked about the order, White House spokesman Jay Carney said the president was committed to transparency and thinks taxpayers should know how their money is being used.

Longtime restrictions on corporate and union political ad spending where eliminated by the the Supreme Court's decision in Citizens United v. FEC. The decision lead to a tsunami of outside political advertising in the 2010 midterm elections.