As President Trump spent Monday sightseeing in India, the U.S. stock market plunged amid growing concerns about a deadly virus spreading quickly across continents — a split-screen that brought into stark relief how the coronavirus is testing the White House and undercutting Trump’s central reelection message. The Trump administration’s disjointed handling of the outbreak has faced mounting criticism as the president’s allies have scrambled to take preventive steps while seeking to reassure the public, at times struggling to explain their decisions and offer a consistent message.

The president’s strategy of publicly downplaying the threat that the virus poses to the United States was undermined Monday as the Dow Jones industrial average — a measure he follows closely — shed more than 1,000 points for its largest drop in two years. Investors acted on growing fears of a worldwide pandemic as the virus took hold in multiple countries, threatening to disrupt global commerce. Trump, who spent Monday visiting the Taj Mahal and other cultural sites, tried to project a sense of calm after the markets closed.

“The Coronavirus is very much under control in the USA,” he wrote on Twitter. “We are in contact with everyone and all relevant countries. CDC & World Health have been working hard and very smart. Stock Market starting to look very good to me!” Minutes later, the president turned to retweeting posts about FBI surveillance, socialism and Republican fundraising.

For a president who has governed “by tweet and circus,” a potential global health crisis that blunts economic growth could expose one of Trump’s main weaknesses as he prepares to face voters in November, said Russell Riley, a presidential historian at the University of Virginia’s Miller Center.