WASHINGTON — Vice President Mike Pence sought to project calm Thursday in his new role as chief coordinator of the government’s response to the coronavirus as the Trump administration rushed to contain mounting public concerns and some of the worst stock market declines in more than a decade.

Pence convened his first meeting of President Donald Trump’s coronavirus task force one day after the president made him the government’s point-person for the epidemic. Pence also tapped a seasoned medical professional to be his chief adviser and said Trump had “tasked us to take every step necessary” to protect the American people.”

The meeting came amid confusion over who was leading the interagency coordinating process to confront the virus. Health and Human Services Secretary Alex Azar stood alongside Trump on Wednesday when the president announced he was putting Pence “in charge” of the government’s virus response.

“I’m leading the task force,” Pence said.

Pence sought Thursday to instill confidence in a jittery public and shaken financial markets by naming Debbie Birx, a medical doctor and the administration’s global AIDS coordinator, to serve as his chief adviser on the virus. He also added Treasury Secretary Steven Mnuchin and Larry Kudlow, director of the National Economic Council, to the task force out of recognition that the situation was quickly becoming an economic threat, too.

The Dow Jones industrial average sank nearly 1,200 points Thursday, deepening a weeklong global market rout caused by worries the virus will wreak economic havoc around the world.