Billionaire fund manager Bill Ackman is calling on President Donald Trump to halt the tariffs on other countries, calling them "unfair asymmetric tariff deals."

Ackman, who endorsed Trump's successful 2024 reelection bid, argues putting disproportionate tariffs on friends and enemies will launch a global and economic war.

"The president has an opportunity to call a 90-day timeout, negotiate and resolve unfair asymmetric tariff deals, and induce trillions of dollars of new investment in our country," Ackman wrote on the social media platform X.

Last week, Trump announced a slew of tariffs on different countries. Since then, leaders of nations such as Israel and Japan have reached out to negotiate a deal.

Meanwhile, other countries such as China have responded with retaliatory tariffs.

Ackman said that the tariffs would negatively impact consumers and CEOs.

"What CEO and what board of directors will be comfortable making large, long-term, economic commitments in our country in the middle of an economic nuclear war?" he wrote. "I don’t know of one who will do so. When markets crash, new investment stops, consumers stop spending money, and businesses have no choice but to curtail investment and fire workers."