The billionaire industrialist Koch brothers, the most powerful conservative mega donors in the United States, will not deploy their $400 million political arsenal to attack Republican front-runner Donald Trump in the U.S. presidential primary election, according to an official from the brothers’ political umbrella group.

"We have no plans to get involved in the primary," said James Davis, spokesman for Freedom Partners, the Koch brothers’ political umbrella group.

Donors and media reports have speculated since a Koch summit in January that the brothers would launch a "Trump Intervention," a strategy that would involve deploying the Koch’s vast political network to target the billionaire reality TV star in hopes of removing him from the race.