Another trade war is brewing – one between President Trump and the Koch brothers.

Days after the president moved forward with imposing steel and aluminum tariffs on the European Union, Canada and Mexico, three political groups affiliated with the billionaire Koch brothers are launching a multi-year, multi-million dollar campaign to tout free trade and oppose tariffs, ABC News has learned.

The campaign, launched by Freedom Partners Chamber of Commerce, Americans for Prosperity and the LIBRE Initiative, all groups funded by the Charles and David Koch, will consist of advertisements, lobbying efforts and grassroots organization.

“This campaign makes a clear statement: Trade is a major priority for our network. We will work aggressively to educate policymakers and others about the facts,” James Davis, executive vice president of Freedom partners said. “Tariffs and other trade barriers make us poorer. They raise prices for those who can least afford it. That’s why this issue is so important,” Davis said. “This announcement is a demonstration of our long-term commitment to advance common-sense trade policies that will ensure America’s brightest days are ahead, and to directly confront the protectionist ideas that would hold us back.”

The move marks one of the biggest splits between the politically powerful Koch network and President Trump. The groups are calling on the president to lift recent tariffs on aluminum and steel imports as well as the proposed tariffs on other imports from China.

They are also asking Congress to require votes on any future tariffs.

“The Trump administration has taken some incredibly positive steps for the American economy, but tariffs will undercut that progress and needlessly hamstring our full economic potential,” Tim Phillips, president of Americans for Prosperity, said. “There are better ways to negotiate trade deals than by punishing American consumers and businesses with higher costs. Instead of pursuing protectionist policies that we already know don’t work, let’s help everyone win by expanding trade, opening new markets and lowering costs.”

Earlier in the day, President Trump tweeted about his recent trade push, saying U.S. farmers are being treated "unfairly" by Mexico, Canada and China, but after his trade negotiations, "that will change."