(Updates death toll)

By Lisa Shumaker

April 20 (Reuters) - U.S. coronavirus deaths topped 42,000 on Monday, according to a Reuters tally, as more protesters gathered in state capitals to demand an early end to the lockdowns, while officials pleaded for patience until more testing becomes available.

Stay-at-home measures, which experts say are essential to slow the spread of the respiratory virus, have ground the economy to a standstill and forced more than 22 million people to apply for unemployment benefits in the last month.

The United States has by far the world's largest number of confirmed coronavirus cases, with more than 774,000 infections, up 20,000 on Monday, with several states yet to report. New reported U.S. cases appear to be slowing from about 30,000 a day last week.

Montana for the first time reported no new cases on Monday after processing 153 tests in the past 24 hours, according to the state's website.

Deaths also have slowed in recent days, rising by about 1,500 so far on Monday compared with over 2,000 a day for most of last week. The United States had a record 2,806 deaths in a single day on Wednesday.

Hot spots are emerging, however, in Chicago, Boston and Philadelphia. Connecticut posted a record increase in cases and deaths as it revised its count due to new classifications from the U.S. Centers for Disease Control and Prevention. The CDC has advised states to count probable, but untested, cases and deaths.

Many of the protesters demanding an end to mandatory lockdowns expressed cynicism toward health experts and skepticism about the actual scale of the pandemic, accusing officials of overreaching and taking actions that had caused more harm than the virus itself.

Health experts and lawmakers on the front lines of the battle to curb the pandemic have warned that the country could face a second and even deadlier wave of infections if the lockdowns end prematurely.

(Writing by Lisa Shumaker; Editing by Howard Goller and Peter Cooney)

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