President Donald Trump and Vice President Mike Pence give a thumbs up after speaking during the first day of the Republican National Convention Monday, Aug. 24, 2020, in Charlotte, N.C. (Travis Dove/The New York Times via AP, Pool)

CHARLOTTE, N.C. (AP) — President Donald Trump turned a surprise opening-day appearance at his party’s scaled-down national political convention into an opportunity to cast doubt on the integrity of the fall election just moments after delegates nominated him for a second term.

“The only way they can take this election away from us is if this is a rigged election,” Trump said as he made an unscheduled appearance at the party’s scaled-down convention. The convention kicked off with a day of “official business” in Charlotte before moving to Washington, D.C. for prime-time programming.

Trump has sought to minimize the toll of the coronavirus pandemic, but its impact was plainly evident at the Charlotte Convention Center, where just 336 delegates gathered instead of the thousands once expected to converge on this city for a week-long extravaganza. Attendees sat at well-spaced tables at first and masks were mandatory, though many were seen flouting the regulation.

Attendees crowded close to the stage when Trump spoke.

The GOP convention is a crucial moment for Trump, who is trailing in national and battleground state polls and under intense pressure to turn the race around. Just 23% think the country is heading in the right direction, while 75% think it’s on the wrong path, according to a new poll from The Associated Press-NORC Center for Public Affairs Research.

The fact that the Republicans gathered at all stood in sharp contrast to the Democrats, who held an all-virtual convention last week.

The Democratic programming included a well-received roll call video montage featuring diverse officials from across the nation. The Republicans spoke from the ballroom and were overwhelmingly white.

Trump said he had made the trip to contrast himself with his Democratic rival, Joe Biden, who never traveled to Wisconsin, the state where the Democratic convention was originally supposed to be held.

And in a nearly hour-long speech, Trump once again sowed doubts about the integrity of November’s election as he laced into mail-in voting, which experts say has proven remarkably safe.

“Be very very careful,” he told the crowd as he concluded. “This is the most important election in the history of the country. Don’t let them take it away from you.”

Trump also panned the state’s Democratic governor for restrictions put in place to try to prevent the spread of the virus, which has killed more than 175,000 people in the country and infected millions. Trump accused Gov. Roy Cooper of “being in a total shutdown mode,” and claimed the restrictions were aimed at trying to hurt his campaign.

Many of the usual trappings of a convention were present on Monday, including signs designating each state and gift bags with Republican swag. But gone was the grandeur, the pomp and the pageantry.

Republicans will spend the week trying to convince the American people that the president deserves a second term. Aides want the convention to recast the story of Trump’s presidency and present the election as a choice between his vision for America’s future and the one presented by Biden.

For both sides, it’s an unconventional convention year.

The parties’ election year gatherings are typically massive events, drawing thousands of delegates, party leaders, donors, journalists and political junkies for a week of speeches, parties and after-parties that inject hundreds of thousands of dollars into the local economy and deliver a multiday infomercial for the nominee.

The coronavirus has changed all that, as much as Trump has resisted. Just 336 delegates — six from each of the 50 states, the District of Columbia and U.S. territories — have been invited to cast proxy votes on behalf of the more than 2,500 regular delegates. And stringent safety measures have been put in place guided by a 42-page health and safety plan developed by a hired doctor.