Trump will explain tariffs on electronics on Monday

President Donald Trump posted for investors not to panic, coining a new term for a party "based on Weak and Stupid people," called a "PANICAN," just minutes before stocks opened on Monday.

"The United States has a chance to do something that should have been done DECADES AGO," the president wrote on Truth Social. "Don’t be Weak! Don’t be Stupid! Don’t be a PANICAN (A new party based on Weak and Stupid people!). Be Strong, Courageous, and Patient, and GREATNESS will be the result!"

Nonetheless, the Dow Jones dropped more 1,000 points at opening.

President Donald Trump touted the U.S. economy in a post to Truth Social on Monday, saying that oil prices, interest rates and other prices are down and claiming -- without providing evidence -- that "the long time abused USA is bringing in Billions of Dollars a week from the abusing countries on Tariffs that are already in place."

"This is despite the fact that the biggest abuser of them all, China, whose markets are crashing, just raised its Tariffs by 34%, on top of its long term ridiculously high Tariffs (Plus!), not acknowledging my warning for abusing countries not to retaliate," Trump wrote.

The president made no mention of the dramatic losses in Asian and European markets on Monday.

ABC News' Michelle Stoddart

JPMorgan Chase CEO Jamie Dimon wrote in a letter to investors published on Monday of his "serious concern" as to how President Donald Trump's tariff policy "will affect America's long-term economic alliances."

"The recent tariffs will likely increase inflation and are causing many to consider a greater probability of a recession," Dimon wrote in JPMorgan Chase's 2024 annual report.

"And even with the recent decline in market values, prices remain relatively high," he added. "These significant and somewhat unprecedented forces cause us to remain very cautious."

"The United States has had a rather healthy and steady economy for years, although it was already weakening as I began writing this letter -- and that was before the recent tariff announcement," he added.

-ABC News' Zunaira Zaki

Key global stock markets tumbled upon opening on Monday as the world's reaction to President Donald Trump's tariffs campaign continued -- and as U.S. futures signaled more turmoil for American markets.

In the U.S., futures for the S&P 500 lost 4.5%, those for the Dow Jones Industrial Average shed 4% and Nasdaq futures lost 4.8% as of Monday morning.

In Japan, the Nikkei 225 index lost nearly 9% shortly after the market opened. Hong Kong's Hang Seng Index dropped more than 13%.

The pan-European Stoxx 600 index dropped more than 6%, Germany's DAX index fell 10%, France's CAC lost 6.6% and Italy's FTSE MIB slid 5.7%. The British FTSE 100 index fell 6% upon opening.