China has been secretly halting exports of major U.S. commodities in a stealthy attempt to undermine Donald Trump's trade war and punish Americans.

While Beijing has matched Trump's 125 percent tariff with one of its own against US-imported goods, they have also been using nontariff barriers to hit the president's supporters the hardest, Politico reported.

Over the past four months, China has halted or significantly curtailed direct key U.S. agriculture and energy exports.

Many of these exports include U.S. farm goods, such beef, poultry and liquified natural gas.

Those resources are largely produced in red states whose voters are far more likely to be Trump supporters, with China likely calculating that any pain people there feel could be used to undermine the president himself.