Kentucky Gov. Andrew Beshear and Secretary of State Michael G. Adams on Monday postponed the state's primary elections, which originally were scheduled for May 19, to June 23 amid concerns about the coronavirus pandemic.

The state becomes the latest in a rapidly growing number to put off their primaries, throwing into question the rest of the 2020 election calendar -- even as voters in three states head to the polls Tuesday.

"I never would have imagined sitting here discussing this with you, but these are unprecedented times," Adams said in a video posted to Twitter. "And we Kentuckians are having to change the way we do things on all fronts. Kentucky law allows the secretary of state and the governor to jointly act to change the time of an election due to a state of emergency."

Only five states and Washington, D.C., originally were scheduled to hold primary elections after Kentucky's May 19 date. The move by Beshear, a Democrat, and Adams, a Republican, could be repeated by officials in states with even earlier primaries in the days ahead.

"Postponing the primary was not an easy decision, but the Republican secretary of state and Democratic governor agree, and so do county clerks of both parties, and they are our frontline election administrators," Adams said. "My hope is that this delay will allow us to have a normal election. Even if not, this delay will allow me, the state board of elections and our county clerks time to assess what changes we must make to ensure a successful primary election. There could be more changes, but this was a first step, to buy us time and keep our citizens as safe as possible. We'll get through this."

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Kentucky's move comes after a lawsuit by Ohio Gov. Mike DeWine earlier Monday to postpone his state's primaries, first scheduled for Tuesday, to June 2. DeWine filed a lawsuit in state court moving to change the election date but it was denied. He later had his state health director Dr. Amy Action order polls closed anyway "as a health emergency" and tasked his secretary of state with working in the courts to officially move the election date so Ohioans could have "free and fair" elections without the risk of catching the coronavirus.

The Ohio Supreme Court, in a ruling without an opinion Tuesday morning, denied a last-second effort to force the state to move ahead with the Tuesday elections, giving further legitimacy to DeWine's 11th-hour maneuver.

Arizona, Florida and Illinois will all hold their presidential primary elections as scheduled on Tuesday.

Ohio previously had joined with the other three states in committing to hold their elections as scheduled, but DeWine, who has been one of the most active governors in fighting the coronavirus, stepped in. He said there was no way the state could make its polling places comply with federal guidelines for limiting gatherings in such a short timeframe.

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Kentucky and Ohio's postponements Monday make five total states or territories in the U.S. that are delaying or moving to delay their primary elections because of the coronavirus. They join Georgia, Louisiana and Puerto Rico.

President Trump on Monday struck a more somber and serious tone in a White House press briefing on the coronavirus threat as his administration released a set of detailed guidelines to help businesses, families and individuals keep themselves and their communities healthy.

Those guidelines included limiting any gatherings to 10 people or fewer, keeping an entire household at home if one person inside tests positive for the coronavirus and washing hands frequently.

Fox News' Paul Steinhauser and Ellison Barber contributed to this report.