By Jennifer Calfas

Confirmed coronavirus cases in the U.S. surpassed two million Thursday, driven in part by surges in states including Arkansas, Florida, Nevada, Oregon and South Carolina, weeks after governors across the nation took steps to reopen their economies.

More than a dozen U.S. states have seen confirmed cases of the new coronavirus increase in the past week at a faster pace than a week earlier, according to a Wall Street Journal analysis of data compiled by Johns Hopkins University.

As the number of confirmed cases topped two million, more than 113,000 Americans have died from the new coronavirus, according to data compiled by Johns Hopkins University. Cases world-wide exceeded 7.4 million, and deaths stood at more than 418,000. Experts say official totals likely understate the extent of the pandemic, in part because of different testing and reporting standards.

Infections have increased rapidly in parts of the Middle East and India, while officials in Europe, once the epicenter of the pandemic, further eased restrictions. India reported its highest number of deaths in a single day Thursday. Fatalities and infections requiring intensive care have surged in Saudi Arabia since the end of May.

In the U.S., stocks tumbled Thursday as concerns of a surge in coronavirus infections sent investors out of risky assets. Increases in cases in states including Texas and California have raised alarms that a second wave of infections could lead to restrictions being applied again to social and business activity.

Florida, for instance, recorded its highest single-day tally of new coronavirus cases with nearly 1,700 reported infections, the state's health department reported Thursday.

For the moment, reopening has continued to stagger forward in some regions.

New York Gov. Andrew Cuomo said five of the state's regions could enter their next phase of reopening Friday -- but urged residents to act cautiously to avoid a rise in infections like those seen in other states.

"The numbers are good, everything we have done has been exactly right up until now. But that's up until now," the Democratic governor said. "You can make a mistake today that wipes out everything we've done, so we have to be smart."

Surges elsewhere have slowed reopening efforts. Nashville Mayor John Cooper said Thursday the city wouldn't ease more restrictions as cases continued to accelerate and affect thresholds needed to enter a new phase.

"The level of cases in southeast Nashville warrants further attention," the mayor said.

Meanwhile, Arkansas Gov. Asa Hutchinson said his state will move into phase two of reopening on June 15, despite a recent rise in cases. The Republican governor attributed the surge to an increase in testing, not the opening of businesses.

Walt Disney Co. said it aims to begin a phased reopening of its Disneyland Resort in July. The plan remains subject to approval by state and local governments, the company said.

But the Coachella Valley Music and Arts Festival and its country sibling, Stagecoach, were canceled by public-health officials, the latest blow to a concert industry that has already weathered months of canceled shows.

As businesses reopen and some recall workers who were furloughed, the labor market appears to be picking up after millions of jobs were lost in March and April. Initial unemployment claims fell to 1.5 million and the number of workers receiving benefits fell slightly to 20.9 million in the latest week, the Labor Department reported Thursday.

But with millions still unemployed, the Trump administration is weighing a second round of stimulus payments for Americans, Treasury Secretary Steven Mnuchin said Thursday. Mr. Mnuchin also said it is extremely unlikely that parts of the U.S. economy will need to shut down again, despite the jump in cases in some parts of the country.

New York City, which launched into its first phase of reopening Monday, is struggling to contain the virus among its homeless population. A report published Tuesday by advocacy group Coalition for the Homeless found the age-adjusted mortality rate for sheltered homeless people in New York City was 321 deaths per 100,000 people, compared with a citywide average of 200 deaths per 100,000 people.

Advocates called on the city and state to provide single-occupancy hotel rooms for people staying in dormitory-style shelters and to ensure that homeless people have access to free virus testing and basic hygiene supplies.

Regeneron Pharmaceuticals Inc. said Thursday it was beginning to test in humans a potential coronavirus drug, the latest therapy to enter clinical trials. If the drug proves to work safely, it could be available for emergency use as early as the fall, Regeneron Chief Scientific Officer George Yancopoulos said.

Meanwhile, a major effort coordinated by the Federal Emergency Management Agency to ship protective gear to nursing homes during the coronavirus pandemic is providing equipment that some facilities say is unusable, including plastic gowns that they say don't meet their infection-control requirements.

The European Union's executive body said countries should remove borders within the bloc and between some neighboring states on June 15, and allow visitors from outside the region to travel there starting July 1. It is unclear whether travelers from the U.S., which currently imposes travel bans on a number of European countries, would qualify. The European Commission wants member states to agree on and keep updating a list of permitted countries, which would provide a boost to tourism in some of the worst-affected countries, including Italy and Spain.

India on Thursday reported 357 additional deaths from Covid-19, the disease caused by the new coronavirus. That is the country's highest single-day tally, bringing the total death toll there to 8,102. Infections surged by 9,996 cases, another single-day record, to 286,579, data from the Ministry of Health and Family Welfare showed. India is the world's fifth-worst-hit country in terms of total infections, after the U.S., Brazil, Russia and the U.K., according to Johns Hopkins data. The state of Maharashtra continues to be the hardest hit, followed by the southern state of Tamil Nadu and Delhi.

A surge in coronavirus cases in Saudi Arabia and other Middle East countries has forced authorities in some places to enforce new lockdown measures.

New daily infections in Saudi Arabia have accelerated since the end of May. The flouting of social-distancing guidelines has caused rapid transmission within Saudi families while more health-care workers are getting sick with the virus. The infection is circulating among the older Saudi population, where chronic conditions such as obesity and diabetes have led to more complications. Total cases now exceed 112,000 with 819 deaths.

Health officials in Australia's Victoria state said a person who attended a Black Lives Matter protest in Melbourne on Saturday was among eight new coronavirus infections in the state. People who attended the protest were urged to get tested and isolate at home if they had any coronavirus symptoms.

Write to Jennifer Calfas at Jennifer.Calfas@wsj.com